Glucose-Operated Widget (GLOW) for Closed-Loop Optogenetic Glycemic Control

Area of Science:

• Biomedical Engineering
• Endocrinology
• Synthetic Biology

Background:

• Closed-loop systems offer precise control for therapeutic gene expression, crucial for chronic diseases like diabetes.
• Engineered pancreatic iβ-cells with melanopsin can rapidly release insulin in response to blue light.
• Current diabetes management requires continuous monitoring and intervention, highlighting the need for advanced control systems.

Purpose of the Study:

• To design a glucose-operated widget (GLOW) for a closed-loop system to control therapeutic insulin release.
• To develop a real-time glucose sensor using a glucose-concentration-dependent fluorescent probe.
• To demonstrate precise, light-inducible insulin secretion from engineered iβ-cells for diabetes treatment.

Main Methods:

• Engineered pancreatic iβ-cells and a glucose-responsive fluorescent probe were encapsulated into hydrogel-microbeads (GLOWiβ).
• The GLOWiβ system was implanted subcutaneously into type-1-diabetic (T1D) mice.
• UV-A light (390 nm) activated the probe, inducing glucose-dependent blue light emission (445 nm) to trigger insulin release.

Main Results:

• UV-A light illumination triggered glucose-concentration-dependent insulin release from GLOWiβ in a reversible manner.
• Subcutaneous activation of GLOWiβ in T1D mice restored normoglycemia within 60-120 minutes.
• The system demonstrated robustness, maintaining normoglycemia with daily activation for at least 7 days.

Conclusions:

• The GLOWiβ system represents a proof-of-concept for a closed-loop, light-controlled artificial pancreas.
• This technology offers a promising strategy for personalized diabetes management through precise glucose regulation.
• The developed system shows potential for long-term, effective control of blood glucose levels in diabetic models.