Novel thermogelling dispersions of polymer nanoparticles for controlled protein release

Study on Novel Nanoparticle Slow-Release Drugs for Moyamoya Disease

Spontaneous basilar artery occlusive disease is a disease characterized by thickening of the intima of the bilateral internal carotid artery and the anterior and middle cerebral arteries, gradually narrowing the arterial diameter, and compensatory dilatation of the perforating artery at the base of the brain. Aspirin (acetylsalicylic acid), as a classic non-steroidal anti-inflammatory drug, has been proven to have antiplatelet, anti-inflammatory, and immune-regulating effects. But how to achieve long-term sustained release of aspirin and achieve anti-platelet aggregation remains to be studied. This study intends to build a microsphere sustained-release system to achieve long-term stable and slow release of aspirin drug, thereby achieving a more ideal anti-platelet aggregation effect. The therapeutic effects of three groups of nanoparticle sustained-release drug regimens on platelet aggregation were compared. The results showed that the platelet inhibition rate and NIHSS scores before treatment were compared between the three groups; compared with the other groups, the PLGA group had higher AA and ADP pathway-induced platelet inhibition rates after treatment and lower plasma Lp-PLA2 and NIHSS scores. This shows that aspirin nanoparticle slow-release drugs can effectively increase platelet inhibition rate and improve the antiplatelet ability of patients with spontaneous basilar artery occlusive disease, which is beneficial to promoting prognosis recovery.

Chemokine releasing particle implants for trapping circulating prostate cancer cells

Prostate cancer (PCa) is the most prevalent cancer in U.S. men and many other countries. Although primary PCa can be controlled with surgery or radiation, treatment options of preventing metastatic PCa are still limited. To develop a new treatment of eradicating metastatic PCa, we have created an injectable cancer trap that can actively recruit cancer cells in bloodstream. The cancer trap is composed of hyaluronic acid microparticles that have good cell and tissue compatibility and can extend the release of chemokines to 4 days in vitro. We find that erythropoietin (EPO) and stromal derived factor-1α can attract PCa in vitro. Animal results show that EPO-releasing cancer trap attracted large number of circulating PCa and significantly reduced cancer spreading to other organs compared with controls. These results support that cancer trap may serve as a unique device to sequester circulating PCa cells and subsequently reduce distant metastasis.

Versatile oligo(ethylene glycol)-based biocompatible microgels for loading/release of active bio(macro)molecules

The present study aims in the understanding of the effect of oligo(ethylene glycol)-based biocompatible microgels inner structure on the encapsulation/release mechanisms of different types of cosmetic active molecules. For that, multi-responsive microgels were synthesized using three types of cross-linkers: ethylene glycol dimethacrylate (EGDMA), oligo(ethylene glycol) diacrylate (OEGDA) and N,N-methylenebisacrylamide (MBA). The inner morphology of the microgels synthesized was studied by ¹H-nuclear magnetic resonance (¹H NMR) and small-angle neutron scattering (SANS) techniques and no effect of cross-linker type on microgel microstructure was observed in the case of analysing purified microgel dispersions. Moreover, all the microgels synthesized presented conventional swelling/de-swelling behavior as a function of temperature and pH. Two hydrophobic, one hydrophilic, and one macromolecule as cosmetic active molecules were effectively loaded into different microgel particles via hydrophobic interactions and hydrogen-bonding interactions between -OH groups of active molecules and ether oxygens of different microgel particles. Their release profiles as a function of cross-linker type used and encapsulated amounts were studied by Peppas-Sahlin model. No effect of the cross-linker type was observed due to the similar inner structure of all the microgels synthesized.

Preparation of a novel injectable in situ-gelling nanoparticle with applications in controlled protein release and cancer cell entrapment

Temperature sensitive injectable hydrogels have been used as drug/protein carriers for a variety of pharmaceutical applications. Oligo(ethylene glycol) methacrylate (OEGMA) monomers with varying ethylene oxide chain lengths have been used for the synthesis of in situ forming hydrogel. In this study, a new series of thermally induced gelling hydrogel nanoparticles (PMOA hydrogel nanoparticles) was developed by copolymerization with di(ethylene glycol) methyl ether methacrylate (MEO₂MA), poly(ethylene glycol) methyl ether methacrylate (300 g mol⁻¹, OEGMA₃₀₀), and acrylic acid (AAc). The effects of acrylic acid content on the physical, chemical, and biological properties of the nanoparticle-based hydrogels were investigated. Due to its high electrostatic properties, addition of AAc increases LCST as well as gelation temperature. Further, using Cy5-labelled bovine serum albumin and erythropoietin (Epo) as model drugs, studies have shown that the thermogelling hydrogels have the ability to tune the release rate of these proteins in vitro. Finally, the ability of Epo releasing hydrogels to recruit prostate cancer cells was assessed in vivo. Overall, our results support that this new series of thermally induced gelling systems can be used as protein control releasing vehicles and cancer cell traps.

At body temperature, thermosensitive nanoparticles release erythropoietin to lure metastatic cancer cells.

Dual-responsive biocompatible microgels as high loaded cargo: understanding of encapsulation/release driving forces by NMR NOESY

The suitability of biocompatible microgels as a new cosmetic carrier has been demonstrated through their ability of encapsulation/release of cosmetic active molecules.

Thermosensitive hydrogels deliver bioactive protein to the vaginal wall

The pathophysiology and natural history of pelvic organ prolapse (POP) are poorly understood. Consequently, our approaches to treatment of POP are limited. Alterations in the extracellular matrix components of pelvic support ligaments and vaginal tissue, including collagen and elastin, have been associated with the development of POP in animals and women. Prior studies have shown the protease MMP-9, a key player of ECM degradation, is upregulated in vaginal tissues from both mice and women with POP. On the other hand, fibulin-5, an elastogenic organizer, has been found to inhibit MMP-9 in the vaginal wall. Hence, we hypothesized that prolonged release of fibulin-5 may delay progression of POP. To test the hypothesis, oligo (ethylene glycol)-based thermosensitive hydrogels were fabricated, characterized and then used to deliver fibulin-5 to the vaginal wall and inhibit MMP-9 activity. The results indicate that hydrogels are cell and tissue compatible. The hydrogels also prolong the ½ life of fibulin-5 in cultured vaginal fibroblasts and in the vaginal wall in vivo. Finally, fibulin-5-containing hydrogels resulted in incorporation of fibulin-5 into the vaginal matrix and inhibition of MMP-9 for several weeks after injection. These results support the idea of fibulin-5 releasing hydrogel being developed as a new treatment for POP.

Myogenic stem cell-laden hydrogel scaffold in wound healing of the disrupted external anal sphincter

OBJECTIVE

To evaluate the effect of myogenic stem cell-laden hydrogel scaffold on contractile function and histomorphology of the external anal sphincter (EAS) after transection without repair.

METHODS

Eighty female rats underwent anal sphincter transection without repair. After 2 weeks, animals were injected at the transection site with: nothing (non-repaired control, NRC group); a polyethylene glycol-based hydrogel matrix scaffold combined with phosphate-buffered saline (PBS/hydrogel group); a hydrogel matrix scaffold combined with myogenic stem cells (stem cell/hydrogel group): or type I collagen (collagen) group. 4 (n = 40) or 12 (n = 40) weeks later, the anal sphincter complexes were dissected out and analyzed for contractile function, disruption, and striated muscle volume. Time-matched unoperated controls (UOC) were utilized for each of the two time points (n = 20).

RESULTS

After 4 weeks, maximal electrical field-stimulated (EFS) contractions were significantly decreased in all four non-repaired treatment groups compared with UOC. However, EFS-stimulated contractions, tetanic force generation, and twitch tension were improved in non-repaired EAS injected with stem cell/hydrogel group relative to the NRC, PBS/hydrogel, or collagen groups. NRC and sphincters injected with PBS/hydrogel deteriorated further by 12 weeks, while those receiving stem cell/hydrogel maintained improved contractile function at varying frequencies and voltages. Striated muscle volume increased from 4 to 12 weeks for PBS/hydrogel and stem cell/hydrogel animals. At 12 weeks, stem cell/hydrogel animals had greater sphincter striated muscle volumes compared with all other treatment groups.

CONCLUSION

In this animal model, sustained improvement of contractile responses in non-repaired EAS treated with biogel scaffold and myogenic stem cells suggests that a biologically compatible matrix may facilitate stem cell survival, differentiation, or function leading to recovery of contractile function even after persistent disruption.

Volume phase transition mechanism of poly[oligo(ethylene glycol)methacrylate] based thermo-responsive microgels with poly(ionic liquid) cross-linkers

Thermodynamic volume phase transition mechanisms of poly[oligo(ethylene glycol)methacrylate] (POEGMA) microgels with poly(ionic liquid) (PIL) cross-linking moieties were investigated in detail on the basis of Fourier transform infrared (FTIR) spectroscopy.

Interpenetrating polymer networks as innovative drug delivery systems

Polymers have always been valuable excipients in conventional dosage forms, also have shown excellent performance into the parenteral arena, and are now capable of offering advanced and sophisticated functions such as controlled drug release and drug targeting. Advances in polymer science have led to the development of several novel drug delivery systems. Interpenetrating polymer networks (IPNs) have shown superior performances over the conventional individual polymers and, consequently, the ranges of applications have grown rapidly for such class of materials. The advanced properties of IPNs like swelling capacity, stability, biocompatibility, nontoxicity and biodegradability have attracted considerable attention in pharmaceutical field especially in delivering bioactive molecules to the target site. In the past few years various research reports on the IPN based delivery systems showed that these carriers have emerged as a novel carrier in controlled drug delivery. The present review encompasses IPNs, their types, method of synthesis, factors which affects the morphology of IPNs, extensively studied IPN based drug delivery systems, and some natural polymers widely used for IPNs.