In the current study, Polylactic acid (PLA)/ Polycaprolactone (PCL)/Bioactive glass (BG) composite filaments were fabricated using reactive extrusion technique followed by the preparation of specimens and prototypes of scaffolds employing fused deposition modeling (FDM) for bone tissue engineering (BTE). Surface modified sol gel process was employed to synthesize dual doped (Mg²⁺/Zn²⁺) BG. Variable concentrations of BG 3wt

Hyaluronic acid (HA) is effective in reducing skin inflammation and sebum production in acne vulgaris. Localized treatment with HA involves rapid dissolving microneedle-based formulations to penetrate and release active ingredients. These causes discomfort and secondary wounds, which eventually aggravate inflammatory responses, thereby increasing the risk of scaring and pathogenesis. This study introduces HA hydrogel film-based thin acne patches made by crosslinking HA with hydrocolloid. These patches exhibit nano to micro scale wrinkle-like morphology, offering uniform adhesion to the skin without additional adhesives or microneedles. The transparent, adhesive, and pliable nature of the patches facilitates seamless integration with the skin. The moisture-retention, stability, breathability, and flexibility parameters ensure the skin mimicking properties enhancing patient compliance. The biphasic HA release facilitates prolonged antioxidant activity and superior bactericidal effects, proving its therapeutic efficacy. Further, the cytocompatibility studies ensure the safety, manifesting the usage in acne therapy. Moreover, the study also demonstrates the incorporation of active ingredients for providing a synergistic effect. This prototype paves the way for a promising localized treatment strategy in several dermatological diseases, indicating a potential future market.

Keratin is an insoluble filamentous sulphur-rich protein constituting the bulk of epidermal appendages, such as hair, chicken feathers, nails, and claws. Being ubiquitously present, keratin's efficacy has been extensively evaluated for different tissue engineering applications. However, to date, no systematic study has investigated and compared two conformationally different keratins sourced from human hair and chicken feathers. The present research emphasizes the comparative therapeutic efficacy of keratins derived from human hair and chicken feathers. Herein, keratins isolated from both sources revealed differences in their molecular weights, as assessed using SDS-PAGE analysis. Notably, human hair-derived keratin (HK) has a molecular weight of 40-60 kDa, while chicken feather-derived keratin (CK) has a molecular weight of ∼10 kDa. FTIR, CD and Raman spectroscopy were performed to assess their conformational features, evidencing the α-helix dominance in HK but β-sheet/turn dominance in CK. Immunological assessment of the macrophage cell line demonstrated the anti-inflammatory property of keratin from each source, where HK showed a significantly higher anti-inflammatory property than CK. Furthermore, in vivo assessment showed that HK-treated wounds exhibit enhanced re-epithelialization and balanced COLI/COLIII deposition, indicating minimal scar formation compared with CK-treated ones. These findings underscore the potential of HK in clinical applications, particularly in wound care and regenerative medicines.

Being an excretory scleroprotein, human hair-derived keratin with inherent bioactive peptide cues may actively participate in an immunomodulatory role in the wound microenvironment. In the current study, nano-microfibrous structural attributes mimicking the extracellular matrix were prepared using a polymer blend containing a high loading of keratin as a bioactive matrix by electrospinning, where polycaprolactone (PCL) was used as an electrospinnable aid. The FESEM analysis showed smooth fibers with diameters ranging from 100 to 220 nm. High keratin loading facilitated improved cellular affinity due to the presence of bioactive peptide cues. Physico-chemical characterization confirmed the presence of protein within the PCL matrix, and the modulus of the material (~25 MPa) was found to be similar to that of native skin. Furthermore, keratin-rich matrices evidenced the potential to modulate macrophages toward M2 macrophages. In vitro assessment with human dermal fibroblasts (HDFs) demonstrated enhanced cytocompatibility-like cellular activity and cell proliferation. In vivo studies evidenced the proactive role of the KPCL matrix in supporting full-thickness wound healing and balancing macrophage activity (CD68 and CD206 immunostaining). Immunohistochemistry and RT-PCR studies showed increased COLI and COLIII expression, evidencing dermal reconstruction within 18 days. Enhanced P63 and K14 expression supported the synergistic role of reepithelialization by the matrix enriched with keratin. Overall, the study showed that the keratin-based matrix facilitates skin wound healing.

Chronic wounds suffer from impaired healing due to microbial attack and poor vascular growth. Thermoresponsive hydrogels gained attention in wound dressing owing to their gelation at physiological temperature enabling them to take the shape of asymmetric wounds. The present study delineates the development of thermoresponsive hydrogel (MCK), from hair-derived keratin (K) and methylcellulose (MC) in the presence of sodium sulfate. The gelation temperature (Tg) of this hydrogel is in the range of 30 °C to 33 °C. Protein-polymer interaction leading to thermoreversible sol-gel transition involved in MCK blends has been analyzed and confirmed by FTIR, XRD, and thermal studies. Keratin, has introduced antioxidant properties to the hydrogel imparted cytocompatibility towards human dermal fibroblasts (HDFs) as evidenced by both MTT and live dead assays. In vitro wound healing assessment has been shown by enhanced migration of HDFs in the presence of MCK hydrogel compared to the control. Also, CAM assay and CD31 expression by the Wistar rat model has shown increased blood vessel branching after the implantation of MCK hydrogel. Further, in vivo study, demonstrated MCK efficacy of hydrogel in accelerating full-thickness wounds with minimal scarring in Wistar rats, re-epithelialization, and reinstatement of the epidermal-dermal junction thereby exhibiting clinical relevance for chronic wounds.

In clinical practice to treat complex injuries, the application of electrical stimulation (ES) directly to the skin complicates the wound. In this work, the effect of a conductive hydrogel mediated electric field on skin regeneration is investigated. Polypyrrole incorporated matrices of gelatin and silk fibroin were prepared by two-step interfacial polymerization. The maximum electrical conductivity of 10-4 S cm-1 was achieved when 200 mM polypyrrole was loaded. Mechanically stable and cytocompatible hydrogels were evidenced to have antioxidant and blood compatible characteristics. Human dermal fibroblast cells responded to pulsed stimulation of 100 or 300 mV mm-1 as observed from the increased expressions of TGFβ1, αSMA, and COLIAI genes. Further, the increase in the αSMA protein expression with the magnitude of electrical stimulation also suggested transdifferentiation of the fibroblast to myofibroblast. Moreover, Raman spectroscopy identified two fingerprint regions (collagen and lipid) to differentiate ES treated and nontreated samples. Therefore, the combination of hydrogels and electrical stimulation has potential therapeutic effects for accelerating the rate of skin regeneration.

The human placenta and umbilical cord, natural birth biowaste, are a housing unit for numerous bioactive macromolecules, growth factors, collagen and GAGs, with an array of high-quality stem cells. MSCs isolated from the human placenta and umbilical cord are utilized in both research and medical applications due to their sustainable sourcing, high viability, multipotent lineage and potency. They present an unprecedented opportunity in the tissue engineering, biomedical and biotechnology fields with minimal ethical constraints and nominal cost. Considering the world population and daily birth rates, with appropriate utilization and management, they could resolve the MSC shortage in the global stem cell therapy market and present biomedical waste disposal. A considerable number of clinical trials are presently underway where placenta-derived stem cells have been administered for different pathologies. Since the umbilical cord and placenta's primary function is to sustain the fetus until delivery, it has an ample supply of nutrients, proteins and essential factors necessary to assist cell viability and proliferation. Present research and medical applications include the fabrication of ECM-based nanofibers, disease models, micro-tissue, hybrid models and artificial implants. Future utilization of birthing biomedical waste in medical engineering and research will provide a rich and sustainable source of stem cells and extracellular matrix for enhanced biocompatibility and regeneration.

Chronic wounds are the outcome of an imbalanced inflammatory response caused by sustenance of immune microenvironment. In this context, tissue engineered graft played great role in healing wounds but faced difficulty in scar remodelling, immune rejection and poor vascularization. All the limitations faced are somewhere linked with the immune cells involved in healing. In this consideration, immunomodulatory biomaterials bridge a large gap with the delivery of modulating factors for triggering key inflammatory cells responsible towards interplay in the wound micro-environment. Inherent physico-chemical properties of biomaterials substantially determine the nature of cell-materials interaction thereby facilitating differential cytokine gradient involved in activation or suppression of inflammatory signalling pathways, and followed by surface marker expression. This review aims to systematically describe the interplay of immune cells involved in different phases in the wound microenvironment and biomaterials. Additionally, it also focuses on modulating innate immune cell responses in the context of triggering the halted phase of the wound healing, i.e., inflammatory phase. The various strategies are highlighted for modulation of wound microenvironment towards wound regeneration including stem cells, cytokines, growth factors, vitamins, and anti-inflammatory agents to induce interactive ability of biomaterials with immune cells. The last section focuses on prospective approaches and current potential strategies for wound regeneration. This includes the development of different models to bridge the gap between mouse models and human patients. Emerging new tools to study inflammatory response owing to biomaterials and novel strategies for modulation of monocyte and macrophage behaviour in the wound environment are also discussed.

Bone tissue engineering (BTE) is an evolving domain and provides encouraging solution to address the current demands in the orthopaedic healthcare system. However, even a well-exploited biomaterial such as synthetic hydroxyapatite (nHAp) fails to induce ideal bone regeneration in the complex in vivo conditions owing to its poor angiogenic potential. Hence, in addition to the osteogenic property, designing smart biomaterials with intrinsic angiogenic property is key for the success of bone tissue engineering implants. Recently, gum tragacanth (TG) has been testified to imbibe both angiogenic and osteogenic characteristics. In this context, TG functionalized nano-hydroxyapatite (TG-HAp) would be an ideal angiogenic-osteogenic material for BTE application. Here, we have reported the biofunctionalization of nHAp with TG through a silanized nHAp intermediate, and its osteogenic and angiogenic properties. X-ray diffraction (XRD) revealed the crystalline apatite phase of HAp. Biofunctionalization of nHAP with TG was confirmed both qualitatively and quantitatively by FTIR and TGA analysis respectively. TEM analysis confirmed the formation of needle shaped nanoparticles having size range (100-300 nm). Biofunctionalization lead to a change in zetapotential of nHAp from - 8.1 mV to 0.1 mV. The existence of multi-layered gum tragacanth on nHAp was confirmed by BET analysis. TG-HAp was found osteogenic when tested invitro using MG-63, (human osteoblast cells) and hMSCs, (human mesenchymal stem cells). Further, TG-HAp was found to increase the cellular VEGF expression in MG-63. Angiogenic property of TG-HAp was confirmed by in vitro tube formation of human umbilical vein endothelial cells (HUVECs). The study altogether indicates about the angiogenic and osteogenic potential of synthesized TG-HAp, which may be used as a new biomaterial in bone tissue engineering.

Regeneration of cartilage still possesses considerable challenge in orthopedic treatment owing to avascular nature and lack of self-healing ability of the tissue. In this context, cartilage defect recovery via engineered functional micro tissue delivery is an emerging trend in musculoskeletal therapeutics. This work explores the efficacy of Capra ear-derived functionalized micro-tissues (FMTs) for regeneration of cartilage defects. For this study, a novel and inexpensive NaOH-based decellularization method was developed and optimized to obtain complete removal of cells without deteriorating the matrix structure of Capra ear cartilage. The decellularized matrix was then processed to generate micro-scaffolds (MSs) with different size distributions. It was established that among those size groups, MSs having 100 µm average size were most effective for adherence, cell proliferation and differentiation. It was assessed that the loose fibrous structure of smaller scaffolds was able to induce chondrogenic differentiation. Further, a frugal system was devised for performing hanging culture on the MSs with adipose tissue derived mesenchymal stem cells (ADMSCs) to generate functionalized micro tissues (FMTs). Finally, FMTs were implanted in rabbit auricular cartilage defects to evaluate their healing efficacy. Histology, FTIR and microCT studies revealed that the implanted FMTs were able to regenerate the defect within 60 days. Thus, this work establishes that the functionalized micro tissues derived from decellularized capra ear cartilage can potentially be used for cartilage regeneration, and the efficacy of regeneration depends on the size along with the fibrous structure of the scaffolds.

Collagen II (COLII), the most abundant protein in vertebrates, helps maintain the structural and functional integrity of cartilage. Delivery of COLII from animal sources could improve cartilage regeneration therapies. Here we show that COLII can be purified from the Capra ear cartilage, a commonly available bio-waste product, with a high yield. MALDI-MS/MS analysis evidenced post-translational modifications of the signature triplet, Glycine-Proline-Hydroxyproline (G-P-Hyp), in alpha chain of isolated COLII (COLIIA1). Additionally, thirty-two peptides containing 59 Hyp residues and a few G-X-Y triplets with positional alterations of Hyp in COLIIA1 are also identified. Furthermore, we show that an injectable hydrogel formulation containing the isolated COLII facilitates chondrogenic differentiation towards cartilage regeneration. These findings show that COLII can be isolated from Capra ear cartilage and that positional alteration of Hyp in its structural motif, as detected by newly developed mass spectrometric method, might be an early marker of cartilage disorder.