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Biology subjects

Feig, V. R.

Publications and source records attributed to Feig, V. R..

2 recordsLinked to original sources

An ingestible, battery-free, tissue-adhering robotic interface for non-invasive and chronic electrostimulation of the gut

Ingestible electronics have the capacity to transform our ability to effectively diagnose and potentially treat a broad set of conditions. Current applications could be significantly enhanced by addressing poor electrode-tissue contact, lack of navigation, short dwell time, and limited battery life. Here we report the development of an ingestible, battery-free, and tissue-adhering robotic interface (IngRI) for non-invasive and chronic electrostimulation of the gut, which addresses challenges associated with contact, navigation, retention, and powering (C-N-R-P) faced by existing ingestibles. We show that near-field inductive coupling operating near 13.56 MHz was sufficient to power and modulate the IngRI to deliver therapeutically relevant electrostimulation, which can be further enhanced by a bio-inspired, hydrogel-enabled adhesive interface. In swine models, we demonstrated the electrical interaction of IngRI with the gastric mucosa by recording conductive signaling from the subcutaneous space. We further observed changes in plasma ghrelin levels, the "hunger hormone," while IngRI was activated in vivo, demonstrating its clinical potential in regulating appetite and treating other endocrine conditions. The results of this study suggest that concepts inspired by soft and wireless skin-interfacing electronic devices can be applied to ingestible electronics with potential clinical applications for evaluating and treating gastrointestinal conditions.

bioengineering↗

Drinkable, liquid in situ-forming and tough hydrogels for gastrointestinal therapeutics

Tablets and capsules are a cornerstone of medicine, but these solid dosage forms can be challenging to swallow for geriatric and pediatric patients. While liquid formulations are easier to ingest, these formulations lack the capacity to localize therapeutics and excipients nor act as controlled release devices. To bridge the advantages of solid and liquid dosage forms, here we describe drug formulations based on liquid in situ-forming and tough (LIFT) hydrogels. Drug-loaded LIFT hydrogels are formed directly in the stomach through the sequential ingestion of a crosslinker solution of calcium and dithiol crosslinkers, followed by the ingestion of a drug-containing polymer solution of alginate and 4-arm poly(ethylene glycol)-maleimide. We show that LIFT hydrogels are mechanically tough and able to robustly form in the presence of complex gastric fluid and in vivo in rat and porcine stomachs. LIFT hydrogels are retained within the porcine stomach for up to 24 h, biocompatible, and safely cleared. These hydrogels deliver a total dose comparable to unencapsulated drug but with delayed and lower maximum drug plasma concentrations, providing a method for controlled release that may mitigate drug toxicity. Co-encapsulation of lactase as a model biologic drug and calcium carbonate mitigated gastric-mediated deactivation of encapsulated enzyme in rat and porcine models. We also demonstrate the potential of these hydrogels to encapsulate and protect a model therapeutic bacterium, E. coli Nissle 1917, against acid. LIFT hydrogels present a biocompatible means of tough, double-network hydrogel formation in situ in the gastric cavity, and may expand medication access for patients with difficulty swallowing.

bioengineering↗