Early-stage in vivo evaluation of microrobot navigation controllability and acute device-tissue interaction remains methodologically underdeveloped. In vitro and ex vivo approaches often fail to balance technological readiness, physiologic relevance, and reproducibility. To address this gap, here we present a non-survival, acute in vivo endovascular testbed in the rat inferior vena cava (IVC). Rat IVC supports studying microrobots with characteristic sizes of 0.1-4 mm and integrates key methodological components, including vascular access, continuous blood flow, anticoagulation strategies, fluoroscopic imaging guidance, and acute in vivo performance benchmarking. The testbed enables systematic assessment of minimum viable in vivo performance metrics for early-stage endovascular microrobots, including image-guided navigation success rate, traversal time, path deviation, acute vessel interaction, deployment/retrieval and device integrity. Common failure modes and practical troubleshooting strategies are provided to support reproducibility across laboratories. The non-survival design is a deliberate methodological choice that isolates acute, engineering-relevant performance while avoiding confounding long-term biological responses. Accordingly, the protocol addresses questions of early design feasibility and control performance but does not evaluate chronic biocompatibility or therapeutic efficacy. By establishing a reproducible intermediate validation stage, this testbed de-risks subsequent survival and large-animal studies in translational microrobot development.

Hemodialysis for chronic kidney disease (CKD) relies on vascular access (VA) devices, such as arteriovenous fistulas (AVF), grafts (AVG), or catheters, to maintain blood flow. Nonetheless, unpredictable progressive vascular stenosis due to neointimal formation or complete occlusion from acute thrombosis remains the primary cause of mature VA failure. Despite emergent surgical intervention efforts, the lack of a reliable early detection tool significantly reduces patient outcomes and survival rates. This study introduces a soft, wearable device that continuously monitors blood flow for early detection of VA failure. Using thermal anemometry, integrated sensors noninvasively measure flow changes in large vessels. Bench testing with AVF and AVG models shows agreement with finite element analysis (FEA) simulations, while human and preclinical swine trials demonstrate the device's sensitivity. Wireless adaptation could enable at-home monitoring, improving detection of VA-related complications and survival in CKD patients.

Enterocutaneous fistulas (ECF) are challenging to treat contributing to high morbidity and high mortality rates, significantly impacting the quality of life of the patients. Its susceptibility to antibiotic-resistant infections often leads to chronic inflammation, complicating treatment with conventional methods. Here, 18NC75-10P-1IL is reported, which is a multi-functional shear-thinning hydrogel comprised of gelatin and nanosilicates for injectability, an ionic liquid for bactericidal effects, and platelet rich fibrin fraction for pro-healing properties; this biomaterial is engineered for the treatment of ECFs. Through rigorous testing, the mechanical properties of 18NC75-10P-1IL were tailored for catheter injection to achieve durable occlusion of fistulous tracts under external pressures simulating clinical scenarios. 18NC75-10P-1IL demonstrated pro-healing effects and anti-microbial activity against highly resistant patient-derived bacteria known to be associated with ECF. Subcutaneous implantation and anorectal fistula models confirmed its biocompatibility, pro-healing, anti-inflammatory, and anti-microbial properties compared to control materials, suggesting promising potential for clinical translation in the treatment of human ECFs.

Enterocutaneous fistulas (ECFs) profoundly impact patients' quality of life, contributing to high morbidity rates and increased mortality due to ineffective treatment options. To address this challenge, ECFGel, a multifunctional, tissue adhesive injectable hydrogel, designed to occlude, sterilize, and promote healing of ECF tracts, is developed. ECFGel is formulated using gelatin and oxidized dextran (O-Dex) as base components, which form chemical crosslinks within the hydrogel and with surrounding biological tissues, ensuring tissue adhesiveness. A choline and geranate-based ionic liquid (IL) is incorporated to provide dual functionality, potent antimicrobial activity, and mechanical enhancement. By optimizing IL concentration, ECFGel achieves rapid gelation, enhanced mechanical strength, and improved elastic recoverability. Additionally, iohexol (IOH) is added for radiopacity, enabling real-time imaging and further strengthening the hydrogel's mechanical properties. ECFGel demonstrates antiswelling properties, biodegradability, and effective tract occlusion in porcine soft tissues. It shows strong antimicrobial activity against highly resistant, patient-derived pathogens isolated from clinical ECF cases. In a porcine perianal fistula model, ECFGel enables rapid occlusion and complete healing, promoting tissue maturation, reducing bacterial load, and increasing markers of cell proliferation and vascularization compared to untreated controls. These promising results highlight ECFGel's potential as a new therapeutic option for treating infected ECFs.

Delivery of therapeutics to solid tumors with high bioavailability remains a challenge and is likely the main contributor to the ineffectiveness of immunotherapy and chemotherapy. Here, a catheter-directed ionic liquid embolic (ILE) is bioengineered to achieve durable vascular embolization, uniform tissue ablation, and drug delivery in non-survival and survival porcine models of embolization, outperforming the clinically used embolic agents. To simulate the clinical scenario, rabbit VX2 orthotopic liver tumors are treated showing successful trans-arterial delivery of Nivolumab and effective tumor ablation. Furthermore, similar results are also observed in human ex vivo tumor tissue as well as significant susceptibility of highly resistant patient-derived bacteria is seen to ILE, suggesting that ILE can prevent abscess formation in embolized tissue. ILE represents a new class of liquid embolic agents that can treat tumors, improve the delivery of therapeutics, prevent infectious complications, and potentially increase chemo- and immunotherapy response in solid tumors.

Deep venous thrombosis (DVT) is a medical condition with significant post-event morbidity and mortality coupled with limited treatment options. Treatment strategy and efficacy are highly dependent on the structural composition of the thrombus, which evolves over time from initial formation and is currently unevaluable with standard clinical testing. Here, we investigate the use of intravascular polarization-sensitive optical coherence tomography (PS-OCT) to assess thrombus morphology and composition in a rat DVT model in-vivo, including changes that occur over the thrombus aging process. PS-OCT measures tissue birefringence, which provides contrast for collagen and smooth muscle cells that are present in older, chronic clots. Thrombi in the inferior vena cava of two cohorts of rats were imaged in-vivo with intravascular PS-OCT at 24 hours (acute, nrats = 3, 73 cross-sections) or 28 days (chronic, nrats = 4, 41 cross-sections) after thrombus formation. Co-registered histology was labelled by an independent pathologist to establish ground-truth clot composition. Automated analysis of OCT cross-sectional images differentiated acute and chronic thrombi with 97.6% sensitivity and 98.6% specificity using a linear discriminant model comprised of both polarization and conventional OCT metrics. These results support PS-OCT as a highly sensitive imaging modality for the assessment of DVT composition to differentiate acute and chronic thrombi. Intravascular PS-OCT imaging could be integrated with advanced catheter-based treatment strategies and serve to guide therapeutic decision-making and deployment, by offering an accurate assessment of DVT patients in real time.

Interventional immuno-oncology is making strides in locoregional therapies to address complex tumor microenvironments. Long-standing interventional radiology cancer therapies, such as tumor ablation and embolization, are being recharacterized in the context of immunotherapy. Intratumoral injections, such as those of genetically engineered or unaltered viruses, and the delivery of immune cells, antibodies, proteins, or cytokines into targeted tumors, along with advancements in delivery techniques, have produced promising results in preliminary studies, indicating their antitumor effectiveness. Emerging strategies using DNA scaffolding, polysaccharides, glycan, chitosan, and natural products are also showing promise in targeted cancer therapy. The future of interventional immuno-oncology lies in personalized immunotherapies that capitalize on individual immune profiles and tumor characteristics, along with the exploration of combination therapies. This study will review various interventional immuno-oncology strategies and emerging technologies to enhance delivery of therapeutics and response to immunotherapy.

Persistent or recurrent bleeding from microvessels inaccessible for direct endovascular intervention is a major problem in medicine today. Here, an innovative catheter-directed liquid embolic (P-LE) is bioengineered for rapid microvessel embolization to treat small vessel hemorrhage. Tested in rodent, porcine, and canine animal models under normal and coagulopathic conditions, P-LE outperformed clinically used embolic materials in both survival and non-survival experiments, effectively occluding vessels as small as 40 microns with no signs of recanalization. P-LE occlusion is independent of the coagulation cascade, and its resistance to displacement is ≈ 8 times greater than systolic blood pressure. P-LE is also found to be biocompatible and x-ray visible and does not require polymerization or a chemical reaction to embolize. To simulate the clinical scenario, acute microvascular hemorrhage is created in the pig kidney, liver, or stomach; these are successfully treated with P-LE achieving immediate hemostasis. Furthermore, P-LE is found to be bactericidal to highly resistant patient-derived bacteria, suggesting that P-LE may also protect against infectious complications that may occur following embolization procedures. P-LE is safe, easy to use, and effective in treating -microvessel hemorrhage.

Benign prostatic hyperplasia and prostate cancer are often associated with lower urinary tract symptoms, which can severely affect patient quality of life. To address this challenge, we developed and optimized an injectable compound, prostate ablation and drug delivery agent (PADA), for percutaneous prostate tissue ablation and concurrently delivered therapeutic agents. PADA is an ionic liquid composed of choline and geranic acid mixed with anticancer therapeutics and a contrast agent. The PADA formulation was optimized for mechanical properties compatible with hand injection, diffusion capability, cytotoxicity against prostate cells, and visibility of an x-ray contrast agent. PADA also exhibited antibacterial properties against highly resistant clinically isolated bacteria in vitro. Ultrasound-guided injection, dispersion of PADA in the tissue, and tissue ablation were tested ex vivo in healthy porcine, canine, and human prostates and in freshly resected human tumors. In vivo testing was conducted in a murine subcutaneous tumor model and in the canine prostate. In all models, PADA decreased the number of viable cells in the region of dispersion and supported the delivery of nivolumab throughout a portion of the tissue. In canine survival experiments, there were no adverse events and no impact on urination. The injection approach was easy to perform under ultrasound guidance and produced a localized effect with a favorable safety profile. These findings suggest that PADA is a promising therapeutic prostate ablation strategy to treat lower urinary tract symptoms.

Embolic materials currently in use for portal vein embolization (PVE) do not treat the tumor, which poses a risk for tumor progression during the interval between PVE and surgical resection. Here, is developed an ionic-liquid-based embolic material (LEAD) for portal vein embolization, liver ablation, and drug delivery. LEAD is optimized and characterized for diffusivity, X-ray visibility, and cytotoxicity. In the porcine renal embolization model, LEAD delivered from the main renal artery reached vasculature down to 10 microns with uniform tissue ablation and delivery of small and large therapeutics. In non-survival and survival porcine experiments, successful PVE is achieved in minutes, leading to the expected chemical segmentectomy, and delivery of a large protein drug (i.e., Nivolumab) with LEAD. In cholangiocarcinoma mouse tumor models and in ex vivo human tumors, LEAD consistently achieved an effective ablation and wide drug distribution. Furthermore, various strains of drug-resistant patient-derived bacteria showed significant susceptibility to LEAD, suggesting that LEAD may also prevent infectious complications resulting from tissue ablation. With its capabilities to embolize, ablate, and deliver therapeutics, ease of use, and a high safety profile demonstrated in animal studies, LEAD offers a potential alternative to tumor ablation with or without PVE for FLR growth.

Advanced-stage liver cancers are associated with poor prognosis and have limited treatment options, often leading the patient to hospice care. Percutaneous intratumoral injection of anticancer agents has emerged as a potential alternative to systemic therapy to overcome tumor barriers, increase bioavailability, potentiate immunotherapy, and avoid systemic toxicity, which advanced-stage cancer patients cannot tolerate. Here, an injectable OncoGel (OG) comprising of a nanocomposite hydrogel loaded with an ionic liquid (IL) is developed for achieving a predictable and uniform tumor ablation and long-term slow release of anticancer agents into the ablation zone. Rigorous mechanical, physiochemical, drug release, cytotoxicity experiments, and ex vivo human tissue testing identify an injectable version of the OG with bactericidal properties against highly resistant bacteria. Intratumoral injection of OG loaded with Nivolumab (Nivo) and doxorubicin (Dox) into highly malignant tumor models in mice, rats, and rabbits demonstrates enhanced survival and tumor regression associated with robust tissue ablation and drug distribution throughout the tumor. Mass cytometry and proteomic studies in a mouse model of colorectal cancer that often metastasizes to the liver indicate an enhanced anticancer immune response following the intratumoral injection of OG. OG may augment immunotherapy and potentially improve outcomes in liver cancer patients.

Central venous catheters are among the most used medical devices in hospitals today. Despite advances in modern medicine, catheter infections remain prevalent, causing significant morbidity and mortality worldwide. Here, SteriGel is reported, which is a multifunctional hydrogel engineered to prevent and treat central line-associated bloodstream infections (CLABSI). The mechanical properties of SteriGel are optimized to ensure appropriate gelation kinetics, bio-adhesiveness, stretchability, and recoverability to promote durability upon application and to provide persistent protection against infection. In vitro assays demonstrated that SteriGel exhibits long-term antimicrobial efficacy and has bactericidal effects against highly resistant patient-derived pathogens known to be frequently associated with CLABSI. SteriGel outperformed Biopatch, which is a clinically used device for CLABSI, in ex vivo cadaver studies that simulate clinical scenarios. Furthermore, SteriGel has biocompatible, pro-healing, and anti-inflammatory properties in vitro and in a rat subcutaneous injection model, suggesting a potential synergistic effect in the prevention and treatment of CLABSI. SteriGel is a multifunctional adherent biomaterial with potent antimicrobial effects for sustained sterility while promoting healing of the catheter incision site to protect against infection.

Ruptured wide-neck aneurysms (WNAs), especially in a setting of coagulopathy, are associated with significant morbidity and mortality. It is shown that by trapping a sub-millimeter clinical catheter inside the aneurysm sac using a flow diverter stent (FDS), instant hemostasis can be achieved by filling the aneurysm sac using a novel biomaterial, rescuing catastrophic bleeding in large-animal models. Multiple formulations of a biomaterial comprising gelatin, nanoclay (NC), and iohexol are developed, optimized, and extensively tested in vitro to select the lead candidate for further testing in vivo in murine, porcine, and canine models of WNAs, including in a subset with aneurysm rupture. The catheter-injectable and X-ray visible versions of the gel embolic agent (GEA) with the optimized mechanical properties outperform control groups, including a subset that receive a clinically used liquid embolic (Onyx, Medtronic), with and without aneurysm rupture. A combinatorial approach to ruptured WNAs with GEA and FDS may change the standard of medical practice and save lives.

Treatment of saccular aneurysms (SAs) depend on their morphology and location. Minimally invasive treatment options include coil embolization, flow diverter stents, stent-assisted coiling and liquid embolics. Many drawbacks are associated with these treatment options. To overcome these drawbacks, we developed and tested a novel biomaterial for the endovascular treatment of SAs in vitro, in cell culture, small and large animal models.

The purpose of the study was to determine whether a single percutaneous needle based injection of an ionic liquid with various therapeutics could be used to ablate normal and tumor tissue, incite inflammation, retain chemotherapy drugs within the ablation zone and achieve uniform delivery of drugs within tissue.

To develop and optimize a nanocomposite hydrogel (EMH) developed to provide outstanding mechanical stability, catheter injectability, retrievability, antibacterial properties, and biological activity for rapid healing to prevent recanalization

Saccular aneurysms (SAs) are focal outpouchings from the lateral wall of an artery. Depending on their morphology and location, minimally invasive treatment options include coil embolization, flow diverter stents, stent-assisted coiling, and liquid embolics. Many drawbacks are associated with these treatment options including recanalization, delayed healing, rebleeding, malpositioning of the embolic or stent, stent stenosis, and even rupture of the SA. To overcome these drawbacks, a nanoclay-based shear-thinning hydrogel (STH) is developed for the endovascular treatment of SAs. Extensive in vitro testing is performed to optimize STH performance, visualization, injectability, and endothelialization in cell culture. Femoral artery saccular aneurysm models in rats and in pigs are created to test stability, efficacy, immune response, endothelialization, and biocompatibility of STH in both ruptured and unruptured SA. Fluoroscopy and computed tomography imaging consistently confirmed SA occlusion without recanalization, migration, or nontarget embolization; STH is also shown to outperform coil embolization of porcine aneurysms. In pigs with catastrophic bleeding due to SA rupture, STH is able to achieve instant hemostasis rescuing the pigs in long-term survival experiments. STH is a promising semisolid iodinated embolic agent that can change the standard of medical practice and potentially save lives.

To develop a patient-derived biomaterial that can be prepared rapidly at point-of-care and achieve embolization better than coil embolization

To develop a biomaterial that is injectable by microcatheters and visible by x-ray, CT, US and MRI, occlusive of the artery even in states of coagulopathy, that is biocompatible and that can achieve safe and durable embolization