title: Agarose surface coating influences intracellular accumulation and enhances payload stability of a nano-delivery system.
abstract: OBJECTIVE
  Protein therapeutics often require repeated administrations of drug over a long period of time. Protein instability is a major obstacle to the development of systems for their controlled and sustained release. We describe a surface modification of nanoporous silicon particles (NSP) with an agarose hydrogel matrix that enhances their ability to load and release proteins, influencing intracellular delivery and preserving molecular stability.
  
  
  METHODS
  We developed and characterized an agarose surface modification of NSP. Stability of the released protein after enzymatic treatment of loaded particles was evaluated with SDS-page and HPLC analysis. FITC-conjugated BSA was chosen as probe protein and intracellular delivery evaluated by fluorescence microscopy.
  
  
  RESULTS
  We showed that agarose coating does not affect NSP protein release rate, while fewer digestion products were found in the released solution after all the enzymatic treatments. Confocal images show that the hydrogel coating improves intracellular delivery, specifically within the nucleus, without affecting the internalization process.
  
  
  CONCLUSIONS
  This modification of porous silicon adds to its tunability, biocompatibility, and biodegradability the ability to preserve protein integrity during delivery without affecting release rates and internalization dynamics. Moreover, it may allow the silicon particles to function as protein carriers that enable control of cell function.
authors: The Methodist Hospital Research Institute (TMHRI), 6670 Bertner Av# Suite R7-114, Houston, Texas 77030, USA.
authors: Enrica
authors: E
authors: De Rosa
authors: Ciro
authors: C
authors: Chiappini
authors: Dongmei
authors: D
authors: Fan
authors: Xuewu
authors: X
authors: Liu
authors: Mauro
authors: M
authors: Ferrari
authors: Ennio
authors: E
authors: Tasciotti
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