John Garner

Fluorescently-endcapped PLGA from Akina, Inc. used as part of oral-insulin delivery research for experimental diabetes treatment

Blog Post created by John Garner on May 16, 2016

PolySciTech division of Akina, Inc. ( provides a wide-array of biodegradable polymers including fluorescently endcapped polymers in the PolyVivo AV*** series. The dye’s conjugated to these polymers absorb a certain wavelength of light and subsequently emit a different wavelength of light allowing for them to be imaged in a manner which eliminates surrounding tissues or other components by applying sharp-cut wavelength filters to the provided light-source and the observation platform (eye piece or camera). A common process simply referred to as fluorescence microscopy. The advantage of these is that nanoparticles or other structures formed using these systems can be imaged and tracked using fluorescence microscopy. Recently PolyVivo AV008 (PLGA-FPR648 MW ~20,000; Abs: 648 nm /Em: 672 nm) was used to track insulin loaded nanoparticles and their penetration into model intestinal cells as part of research to develop an oral (as opposed to the current injection-based systems) insulin delivery system. This system holds the promise for a less-painful treatment option for diabetes. Read more about this exciting research here: Sheng, Jianyong, Huining He, Limei Han, Jing Qin, Sunhui Chen, Ge Ru, Ruixiang Li, Pei Yang, Jianxin Wang, and Victor C. Yang. "Enhancing insulin oral absorption by using mucoadhesive nanoparticles loaded with LMWP-linked insulin conjugates." Journal of Controlled Release (2016).


  “Abstract: Although significant progress has been made, effective oral delivery of protein drugs such as insulin by nanoparticle-based carrier systems still faces certain formidable challenges. Considerable amount of protein drug is released from the nanoparticles (NPs) in the gastrointestinal (GI) tract. Because of their low permeability through the intestinal mucosa, the released protein would be soon degraded by the large amount of proteases in the GI tract. Herein, we report an oral insulin delivery system that can overcome the above-mentioned problems by mucoadhesive NPs (MNPs) loaded with cell penetrating peptide-linked insulin conjugates. On one hand, after conjugation with low molecular weight protamine (LMWP), a cell penetrating peptide (CPP), insulin showed greatly improved permeability through intestinal mucus layer and epithelia. On the other hand, the mucoadhesive N-trimethyl chitosan chloride-coated PLGA nanoparticles (MNPs) that were loaded with conjugates enhanced the retention in the intestinal mucus layer. By adopting this delivery strategy, the LMWP-insulin conjugates released from NPs could be deprived from enzymatic degradation, due to the short distance in reaching the epithelia and the high permeation of the conjugates through epithelia. The oral delivery system of insulin designed by us showed a long-lasting hypoglycemia effect with a faster onset in diabetic rats, with an oral insulin pharmacological availability being 17.98 ± 5.61% relative to subcutaneously injected insulin solution, as well as a 2-fold higher improvement over that by MNPs loaded with native insulin. Our results suggested that conjugation with CPP followed by encapsulation in MNPs provides an effective strategy for oral delivery of macromolecular therapeutics. Keywords: Nanoparticles; Cell-penetrating peptide; Low molecular weight protamine; Insulin; Oral delivery; Mucoadhesion”


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