Implantable long-acting drug delivery systems, such as subcutaneous implants, provide controlled, sustained release of an active ingredient. Although drug release kinetics are critical in the development of such systems, current in vitro release testing methods often fail to account for key physiological parameters such as pH, buffer capacity, flow conditions, as well as tissue/extracellular matrix (ECM) firmness and proteins. This study investigates the long-term in vitro release behavior of two biodegradable dexamethasone-loaded implants with different internal structures: dense implants produced via hot-melt extrusion (HME, 100% infill) and porous implants fabricated via fused filament fabrication (FFF, 25% infill). Phosphate buffers (10 mM and 100 mM), simulated body fluid, and simulated subcutaneous interstitial fluid were evaluated as potential release media. Among the tested buffers, the 100 mM phosphate buffer showed the highest long-term stability, maintaining a consistent buffer capacity with minimal fluctuations in pH and osmolarity and no precipitation at elevated temperatures. Protein-containing media, in general, showed precipitation and degradation and were therefore excluded from further studies. The effect of interstitial fluid flow was evaluated using the USP 4 apparatus, and release was studied over a period of 8 weeks. It was found thatcompared to static conditionsdrug release from porous FFF implants significantly increased from 23.71 ± 1.07% to 25.99 ± 0.41%. In contrast, dense HME implants exhibited diffusion-dominated release that was unaffected by flow. The underlying release mechanism, as determined by Korsmeyer-Peppas modeling, was dominated by diffusion for both implants, consistent with the behavior observed under static release conditions. The influence of tissue/ECM firmness was investigated in a gel-based setup using a 0.5% agarose gel, which allows diffusion of small molecules, mimics the bulk viscoelastic behavior of soft connective tissues/ECM, and shows comparable pore sizes. As expected, the overall drug release and underlying mechanism changed for both implant types, resulting in a lower absolute drug release and elevated n-values. Our findings provide fundamental insights into the interplay between relevant parameters, in particular flow and tissue/ECM firmness, and internal implant structures on the in vitro drug release, offering a framework to improve long-term testing of subcutaneous implants.

Establishing a competitive advantage in the nanomedicine market requires developing high-quality products that meet stringent consumer and regulatory standards. Nanoscale therapeutics must combine clinical efficacy and safety with scalable manufacturing and cost-effectiveness. However, their production is traditionally based on batch manufacturing, which suffers from batch-to-batch variability and prolonged development timelines. Here, we present a continuous impingement jet mixing (IJM) production line for an oil-in-water nano-emulsion, integrated with digital tools for accelerated process development and real-time quality assurance. Nanoemulsions with D50 values below 100 nm were produced at suitable combinations of Reynolds number and phase ratio. Droplet size was monitored inline using a process analytical technology (PAT) tool based on spatially resolved dynamic light scattering (SR-DLS), covering real-time size distributions between 10 and 250 nm under flow. These inline data were used to guide an automated design of experiments (DoE) that systematically varied flow rate, phase ratio and concentrations. Iterative optimization identified operating conditions yielding a narrow droplet size distribution with a mean of 84.8 nm and a standard deviation of 34.3 nm (i.e, target distribution). Based on the real-time monitored signal, material discharge was controlled. Significant shifts from the target PSD or PSD bimodality automatically triggered diversion of out-of-spec material, maintaining consistent product quality throughout production cycles and eliminating holding phases between processing steps This study demonstrates, for the first time, the integration of IJM, SR-DLS, and digital framework in a continuous nanomedicine production line accelerating development timelines, and providing a well-controlled platform for next-generation nanoscale therapeutics.

Microdialysis (MD) and open flow microperfusion (OFM) are promising minimally invasive technologies for continuously sampling local drug concentrations in the interstitial fluid (ISF) of target tissues. However, translating the measured drug concentrations to actual tissue concentrations remains challenging, particularly for highly protein-bound drugs. This study investigated the impact of drug-protein binding, perfusate composition, and diffusion resistance on the measured concentrations of four drugs with different binding affinities to human serum albumin (HSA). MD and OFM were used in in vitro solutions and agar gels with varying HSA concentrations and in ex vivo dermal tissue setups with perfusates containing 0-4 % HSA. Our data showed that in vitro relative recoveries (RRs) were overestimated (>100 %) and strongly influenced by the perfusate's composition for highly protein-bound drugs, with e.g., a fivefold increase observed for diclofenac when comparing a 0 % to a 4 % HSA perfusate. A similar dependence of the RR on the perfusate's composition was observed in gel setups, although to a lesser extent, with the lower RRs reflecting increased diffusion resistance in agar gels compared to solutions. In ex vivo setups, dermal diffusion rather than perfusate composition predominantly influenced sampling efficiency. Unlike the fivefold increase observed in vitro, no significant change in MD RR was found ex vivo, while OFM showed the highest RR with perfusates that matched actual ISF protein concentrations. Our results emphasize that quantitative pharmacokinetic studies, particularly for highly protein-bound drugs, can be considerably optimized by selecting an appropriate combination of sampling technology and perfusate composition, while considering tissue-specific factors.

Loss of implant function is a common complication in orthopaedic and dental surgery. Among the primary causes of implant failure are peri-implant infections which often result in implant removal. This study demonstrates the development of a new antimicrobial titanium coating with ZnO nanoparticles of various sizes and morphologies immobilised in poly(allylamine hydrochloride) and alginate multilayers, combined with epitaxially grown vaterite crystals. The coated samples were characterised with various methods (FTIR, XRD, SEM) and surface properties were evaluated via water contact angle and surface charge measurements. Zinc ion release was quantified using ICP-MS. The antimicrobial efficacy of the coatings was tested against Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans while the biocompatibility was tested with preosteoblast cells (MC3T3-E1). Results demonstrated the successful preparation of a calcium carbonate/ZnO composite coating with epitaxially grown vaterite on titanium surfaces. The Zn ions released from ZnO nanoparticles dramatically influenced the morphology of vaterite where a new flower-like morphology was observed. The coated titanium surfaces exhibited robust antimicrobial activity, achieving over 90% microbial viability reduction for Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. Importantly, the released Zn2+ concentrations remained below the cytotoxicity limit for MC3T3-E1 cells, showing potential for safe and effective implant applications.

Background/Objectives: Continuous manufacturing is gaining importance in the nanopharmaceutical field, offering improved process efficiency and product consistency. To fully leverage its potential, the integration of Process Analytical Technology (PAT) tools is essential for real-time quality control and robust process monitoring. Among the critical quality attributes (CQAs) of nanosystems, particle size plays a key role in ensuring product consistency and performance. However, real-time size monitoring remains challenging due to complex process dynamics and nanosystem heterogeneity. Methods: This study evaluates the applicability of conventional Dynamic Light Scattering (DLS) and spatially resolved DLS (SR-DLS) using the NanoFlowSizer (NFS) as PAT tools in a temperature-regulated top-down nano-production line. Various lipid-based nanosystems, including solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), and nanoemulsions (NEs), were investigated. To ensure reliable implementation, key factors such as sample dilution, viscosity, focus position, measurement angle and temperature effects were systematically assessed for offline and at-line DLS using the Litesizer 500, as well as for offline, inline, and online SR-DLS using the NFS. Results: Offline screening confirmed that selecting the appropriate dilution medium and rate ensures measurement reliability. At-line methods provided an efficient alternative by enabling rapid final product control with minimal manual intervention. Inline and online monitoring further enhanced process efficiency by enabling real-time tracking of size, reducing waste, and allowing immediate process adjustments. Conclusions: This study demonstrates that integrating offline, at-line, in-line, and online DLS techniques allows for comprehensive product monitoring throughout the entire production line. This approach ensures a streamlined process, enables real-time adjustments, and facilitates reliable quality control after production and during storage.

Recently, we established a semi-continuous top-down process enabling the solvent-free production of drug-free lipid-based nanosystems. In this study, the applicability of the established process line to drug-loaded nanosystems was evaluated, focusing on whether process parameters require adjustment upon drug incorporation. Edaravone was selected as a model drug and encapsulated in nanostructured lipid carriers (NLC) composed of Precirol® ATO 5 or Gelucire® 43/01 as solid lipids, combined with Labrafac™ Lipophile WL 1349 or Capryol® 90 as liquid lipids, as well as in nanoemulsions (NEs) consisting solely of the liquid lipids. Integration of the NanoFlowSizer enabled real-time size monitoring via spatially resolved dynamic light scattering (SR-DLS) during Microfluidizer® processing and allowed detection of potential formulation instabilities caused by altered intermolecular interactions following drug incorporation. Design of Experiments (DoE) was employed to optimize encapsulation efficiency (EE%) and loading capacity (LC%). Initial lipid screening revealed superior compatibility of Labrafac™ Lipophile WL 1349 over Capryol® 90 with both solid lipids and edaravone. Gelucire®-based NLC achieved EE% and LC% up to 47 % and 0.9 %, respectively, while Labrafac™-based NEs reached 86 % EE% and 1.7 % LC%. Higher drug concentrations (2 %) led to increased NLC sizes compared to lower concentrations (0.8 %). Lipid type was identified as the most influential formulation parameter, while the solid to liquid lipid ratio and drug concentration had minor effects. Combining inline and offline SR-DLS measurements enabled early detection of subtle instabilities such as micelle formation and particle agglomeration, outperforming conventional offline DLS. Overall, the findings underscore the versatility and robustness of the semi-continuous, solvent-free production line with integrated SR-DLS as a powerful platform for the efficient development of lipid-based nanocarriers with improved drug loading, stability, and process control.

The immunological barrier is among the most significant barriers in vivo. Macrophages and dendritic cells play a crucial role in immune responses, involving phagocytosis, antigen presentation, and triggering adaptive responses. Nanoscale drug-delivery vehicles, such as polymer-encapsulated lipid-bilayer nanodiscs, are of particular interest in the development of new therapeutic approaches, but require well-characterized human in vitro cell models. To this end, the present study differentiated human monocytes into two distinct states, resting macrophages and immature dendritic-like cells (iDCs). These cells served as model systems to assess the efficacy of lipid-bilayer nanodiscs encapsulated by anionic glyco-DIBMA (diisobutylene-maleic acid) or electroneutral sulfo-DIBMA polymers. Nanodisc-cell interaction studies-including cell viability, reactive oxygen species production, cytokine release, particle uptake, and activation marker expression-demonstrated that immune responses depend sensitively on the cell type and polymer and thus on the surface charge of the nanodiscs. Sulfo-DIBMA nanodiscs induced minimal immune cell activation, accompanied by cytokine release and reduced uptake of the nanodiscs by immune cells. In contrast, glyco-DIBMA nanodiscs exhibited increased interactions with cells, elicited pro-inflammatory immune responses, and promoted iDC maturation. This involved co-stimulatory and antigen-presenting molecules, potentially leading to T-cell activation. These findings underscore the potential of glyco-DIBMA nanodiscs to modulate immune responses through receptor-specific interactions, paving the way for immunotherapeutic strategies.

Parents worldwide suffer from their children's frequent refusal to take their medicine - even creams and patches may be refused due to tedious application, painful removal, and caprice. However, children find decorative tattoos appealing. Hence, a personalized drug-loaded temporary tattoo as a novel pediatric dosage form is presented. As a showcase, a pain treatment prototype tattoo based on a lidocaine/prilocaine eutectic was developed. By employing piezoelectric inkjet printing of the drug onto a decorative motif, which can be chosen based on the child's personal preference, the drug content was tailored via variations in the number of deposited layers. To ensure the correct dispensed drug content, non-destructive near-infrared hyperspectral imaging was used and a linear correlation model covering drug doses ranging from 0 to 25 mg cm-2 (R2 0.9925) was established. The drug-loaded tattoos were easily transferred onto the skin and revealed suitable ex-vivo drug permeation into human skin with 0.69 and 0.78 µg·g-1 lidocaine and prilocaine found in the upper dermis after only 30 min. In a nutshell, we hereby introduce a well-controllable and highly acceptable pediatric treatment alternative based on a low-cost additive manufacturing technology.

Effective buccal drug delivery is limited by the barrier properties of the mucosa, necessitating innovative systems to enhance permeability without compromising tissue integrity. In this study, bilosomes composed of sodium glycodeoxycholate and phosphatidylcholine were evaluated as a nanoparticulate platform for buccal drug delivery. Their in vitro uptake was investigated using the TR146 buccal cell line. The bilosomes demonstrated stable physicochemical properties and no aggregation. Functional assays indicated that they transiently opened cell-cell junctions, promoting transport across the mucosal barrier while minimizing toxicity. Quartz crystal microbalance with dissipation monitoring confirmed specific interactions with barrier components, supported by observed modulation of desmosomal junctions and cellular uptake. Ex vivo studies using porcine buccal mucosa further showed concentration-dependent distribution. Collectively, these results suggest that bilosomes are a safe and effective platform for enhancing buccal drug absorption.

Subcutaneous implantable drug delivery systems (SIDDS) offer significant reduction in administration frequency compared to oral dosage forms, which improves patient adherence. However, current manufacturing methods, such as hot melt extrusion, offer limited flexibility for individualizing product specifications (e.g., changes in drug loading or changes in the daily dose) and for providing on-demand solutions. Here, dual-extruder fused filament fabrication was explored for the first time as an advanced manufacturing method to produce biodegradable, drug-loaded SIDDS with customizable release profiles. Seven advanced implant designs (including monolithic and core-shell type implants) were tested to study the impact of 3D-printing parameters (e.g., the internal porosity or shell thickness) on the drug release profile, confirming the suppression of burst release and the achievement of zero-order or tri-phasic release profiles. The implants were further characterized with respect to quality parameters such as shell continuity, shell thickness, and drug content. Overall, this work provides a fundamental framework to produce SIDDS with adaptable release profiles and release time frames through adjustment of 3D-printing parameters.

The prevalence of bacterial infections presents a significant challenge in the medical field, demanding effective strategies to impede bacterial adhesion and growth on various surfaces. The conducted study investigates the efficacy of polyelectrolyte multilayers & horbar;comprising poly(allylamine hydrochloride) (PAH) and alginate (ALG)& horbar;embedded with zinc oxide (ZnO) and copper oxide (CuO) nanoparticles (NPs) to inhibit bacterial adhesion on stainless-steel surfaces. Surface characterization involved zeta potential, contact angle, and roughness assessments. The effect of NP composition, size, and morphology in conjunction with polycation or polyanion terminating multilayers was evaluated against planktonic and surface-adhered Escherichia coli (E. coli) cells. Surfaces with the positively charged PAH-terminating multilayer displayed higher water contact angles (approximate to 63 degrees) than the negatively charged ALG-terminating multilayers (approximate to 45 degrees). Multilayers containing ZnO NPs showed a significant inhibition of planktonic E. coli growth, >99%. Moreover, complete growth inhibition of surface-adhered E. coli was achieved for multilayers containing both ZnO and CuO. Due to their larger specific surface area, rod-like ZnO NPs displayed higher antibacterial activity. The samples with ALG as the terminating layer showed more substantial antibacterial properties than samples with PAH as the terminating layer. Biocompatibility tests on immortalized human keratinocyte cells revealed good compatibility with multilayers incorporating NPs. In summary, this study underscores the potential of ZnO and CuO NPs within PAH/ALG multilayers for antibacterial applications without compromising their cytocompatibility.

A variety of strategies for producing high-quality nanoparticles have been reported in recent years. Batch-based bottom-up and top-down technologies are generally the most efficient methods, but present a number of challenges, particularly in terms of variability, safety, sustainability and large-scale production. In this study, a scalable, semi-continuous production line was built by connecting individual processing units, including a high shear mixing device, the Microfluidizer® technology and a cooling system. Each unit was equipped with an adequate temperature control to allow solvent-free production of solid lipid nanoparticles (consisting of Precirol® ATO 5 or Gelucire® 43/01) and nanostructured lipid carriers (additionally comprising Labrafac™ lipophile WL 1349). Subsequently, critical formulation parameters and critical process parameters (CPPs) of the individual processing units and their effects on particle size (i.e., critical quality attribute (CQA)) were investigated to identify appropriate input parameters for the subsequent Design of Experiment (DoE) studies conducted after linking the process units to a semi-continuous production line. For particle size monitoring, spatially resolved dynamic light scattering (SR-DLS) measurements were conducted and compared to standard DLS measurements to evaluate the applicability of SR-DLS as an inline monitoring tool. It was found that matrix composition, emulsifier concentration, pressure and number of cycles when processing through Microfluidizer® processor were the most influencing parameters. By optimizing these parameters, five-times higher throughputs could be achieved by the semi-continuous manufacturing line. In addition, the particle size measurements with SR-DLS confirmed the feasibility of implementing this technology for real-time particle size monitoring as an important safety factor in quality control.

In this work, filament-based 3D-printing, the most widely used sub-category of material extrusion additive manufacturing (MEAM), is presented as a promising manufacturing platform for the production of subcutaneous implants. Print nozzle diameters as small as 100 mu m were utilized demonstrating MEAM of advanced porous internal structures at the given cylindrical implant geometry of 2 mm x 40 mm. The bottlenecks related to highresolution MEAM of subcutaneous implants are systematically analyzed and the print process is optimized accordingly. Custom synthesized biodegradable phase-separated poly(ether ester) multiblock copolymers exhibiting appropriate melt viscosity at comparatively low printing temperatures of 135 degrees C and 165 degrees C were utilized as 3D-printing feedstock. The print process was optimized to minimize thermomechanical polymer degradation by employing print speeds of 30 mm center dot s- 1 in combination with a nozzle diameter of 150 mu m at layer heights of 110 mu m. These results portray the basis for further development of subcutaneous implantable drug delivery systems where drug release profiles can be tailored through the adaption of the internal implant structure, which cannot be achieved using existing manufacturing techniques.

The efficacy of nanostructured lipid carriers (NLC) for drug delivery strongly depends on their stability and cell uptake. Both properties are governed by their compositions and internal structure. To test the effect of the lipid composition of NLC on cell uptake and stability, three kinds of liquid lipids with different degrees of unsaturation are employed. After ensuring homogeneous size distributions, the thermodynamic characteristics, stability, and mixing properties of NLC are characterized. Then the rates and predominant pathways of cell uptake are determined. Although the same surfactant is used in all cases, different uptake rates are observed. This finding contradicts the view that the surface properties of NLC are dominated by the surfactant. Instead, the uptake rates are explained by the structure of the nanocarrier. Depending on the mixing properties, some liquid lipids remain inside the nanocarrier, while other liquid lipids are present on the surface. Nanocarriers with liquid lipids on the surface are taken up more readily by the cells. This shows that the engineering of efficient lipid nanocarriers requires a delicate balance of interactions between all components of the nanocarrier on the molecular level.

Nasal systemic drug delivery may provide an easy way to substitute parenteral or oral dosing, however, the excipients have an important role in nasal formulations to increase the permeability of the mucosa and prolong the residence time of the drug. In this work, we aimed to produce meloxicam potassium monohydrate (MXP) containing nasal powders by a nano spray drier with the use of a neutral, an anionic and a cationic β-cyclodextrin as permeation enhancers, and (polyvinyl)alcohol (PVA) as a water soluble polymer. The following examinations were performed in order to study the effect of the applied excipients on the nasal applicability of the formulations: laser scattering, scanning electron microscope measurement, XRPD, DSC and FTIR measurements, adhesivity, in vitro drug release and permeability tests through an artificial membrane and RPMI 2650 cells. Based on our results, spherical particles were prepared with a size of 1.89-2.21 µm in which MXP was present in an amorphous state. Secondary interactions were formed between the excipients and the drug. The charged cyclodextrin-based formulations showed significantly higher adhesive force values regardless of the presence of PVA. The drug release was fast and complete. The passive diffusion of MXP was influenced not only by the charge of the cyclodextrin, but the presence of PVA, too. The permeation of the drug was enhanced in the presence of the anionic cyclodextrin testing it on RPMI 2650 cell model.

Plastic pollution in aquatic ecosystems has become a significant problem especially microplastics which can encapsulate into the skeletons of organisms that produce calcium carbonates, such as foraminifera, molluscs and corals. The encapsulation of microplastics into precipitated aragonite, which in nature builds the coral skeleton, has not yet been studied. It is also not known how the dissolved organic matter, to which microplastics are constantly exposed in aquatic ecosystems, affects the encapsulation of microplastics into aragonite and how such microplastics affect the mechanical properties of aragonite. We performed aragonite precipitation experiments in artificial seawater in the presence of polystyrene (PS) and polyethylene (PE) microspheres, untreated and treated with humic acid (HA). The results showed that the efficiency of encapsulating PE and PE-HA microspheres in aragonite was higher than that for PS and PS-HA microspheres. The mechanical properties of resulting aragonite changed after the encapsulation of microplastic particles. A decrease in the hardness and indentation modulus of the aragonite samples was observed, and the most substantial effect occurred in the case of PE-HA microspheres encapsulation. These findings raise concerns about possible changes in the mechanical properties of the exoskeleton and endoskeleton of calcifying marine organisms such as corals and molluscs due to the incorporation of pristine microplastics and microplastics exposed to dissolved organic matter.

In the field of precision medicine, therapy is optimized individually for each patient, enhancing efficacy while reducing side effects. This involves the identification of promising drug candidates through high-throughput screening on human derived cells in culture. However, screening of drugs which have poor solubility or permeability remains challenging, especially when targeting intracellular components. Therefore, encapsulation of drugs into advanced delivery systems such as nanostructured lipid carries (NLC) becomes necessary. Here we show that the cellular uptake of NLC with different matrix compositions can be assessed in a high-throughput screening system based on acoustic droplet ejection (ADE) technology (Echo liquid handler). Our findings indicate that surface tension and viscosity of the NLC dispersions need to be tailored to enable a reliable ADE transfer. The automated NLC uptake studies indicated that the composition of the matrix, more specifically the amount of oleic acid, significantly influenced cellular uptake. The data obtained were corroborated by imaging based and spectral flow cytometry cellular uptake studies. These findings thus not only provide the basis for a screening tool to rapidly identify the efficacy of NLC uptake but also enable a next step toward precision high-throughput drug screening under consideration of an optimized drug delivery system.

Orally administered drugs pass through the gastrointestinal tract before being absorbed in the small intestine and metabolised in the liver. To test the efficacy and toxicity of drugs, animal models are often employed; however, they are not suitable for investigating drug-tissue interactions and making reliable predictions, since the human organism differs drastically from animals in terms of absorption, distribution, metabolism and excretion of substances. Likewise, simple static in vitro cell culture systems currently used in preclinical drug screening often do not resemble the native characteristics of biological barriers. Dynamic models, on the other hand, provide in vivo-like cell phenotypes and functionalities that offer great potential for safety and efficacy prediction. Herein, current microfluidic in vitro intestinal and hepatic models are reviewed, namely single- and multi-tissue micro-bioreactors, which are associated with different methods of cell cultivation, i.e., scaffold-based versus scaffold-free.

Silica (SiO2), titanium dioxide (TiO2), and zinc oxide (ZnO) nanoparticles (NPs) are widely used in dermal products. Their skin sensitization potential, especially their effects in combination with known sensitizers, is poorly studied in vitro and their sensitization inconsistently reported in animal studies. In this study, cellular assays were used to identify different steps of sensitization, the activation of keratinocytes and dendritic cells, when cells were exposed to these NPs in the absence and presence of sensitizers. Cellular systems included HaCaT keratinocytes and U937 (U-SENS™) alone, as well as different co-culture systems of THP-1 cells with HaCaT cells (COCAT) and with primary keratinocytes. The effect of NPs differed between co-cultures and U-SENS™, whereas co-cultures with either primary keratinocytes or HaCaT cells responded similarly. Pre-exposure to ZnO NPs increased the U-SENS™ assay response to 2,4-dinitrochlorobenzene six-fold. The COCAT increase was maximally four-fold for the combination of SiO2 and trans cinnamaldehyde. When the THP-1 cells were separated from the keratinocytes by a membrane, the response of the co-culture system was more similar to U-SENS™. The direct contact with keratinocytes decreased the modulating effect of TiO2 and ZnO NPs but suggested an increase in response to sensitizers following dermal contact with SiO2 NPs.

In healthcare facilities, infections caused by Staphylococcus aureus (S. aureus) from textile materials are a cause for concern, and nanomaterials are one of the solutions; however, their impact on safety and biocompatibility with the human body must not be neglected. This study aimed to develop a novel multilayer coating with poly(allylamine hydrochloride) (PAH) and immobilized ZnO nanoparticles (ZnO NPs) to make efficient antibacterial and biocompatible cotton, polyester, and nylon textiles. For this purpose, the coated textiles were characterized with profilometry, contact angles, and electrokinetic analyzer measurements. The ZnO NPs on the textiles were analyzed by scanning electron microscopy and inductively coupled plasma mass spectrometry. The antibacterial tests were conducted with S. aureus and biocompatibility with immortalized human keratinocyte cells. The results demonstrated successful PAH/ZnO coating formation on the textiles, demonstrating weak hydrophobic properties. Furthermore, PAH multilayers caused complete ZnO NP immobilization on the coated textiles. All coated textiles showed strong growth inhibition (2–3-log reduction) in planktonic and adhered S. aureus cells. The bacterial viability was reduced by more than 99%. Cotton, due to its better ZnO NP adherence, demonstrated a slightly higher antibacterial performance than polyester and nylon. The coating procedure enables the binding of ZnO NPs in an amount (<30 µg cm−2) that, after complete dissolution, is significantly below the concentration causing cytotoxicity (10 µg mL−1).