Enhanced photoluminescence of porous silicon nanoparticles coated by bioresorbable polymers

Maxim B Gongalsky,Bong Hyun Chung,Liubov A Osminkina,Victor Yu Timoshenko,Han Lee,Alexander Yu Kharin,Jinyoung Jeong

doi:10.1186/1556-276x-7-446

Abstract

A significant enhancement of the photoluminescence (PL) efficiency is observed for aqueous suspensions of porous silicon nanoparticles (PSiNPs) coated by bioresorbable polymers, i.e., polylactic-co-glycolic acid (PLGA) and polyvinyl alcohol (PVA). PSiNPs with average size about 100 nm prepared by mechanical grinding of electrochemically etched porous silicon were dispersed in water to prepare the stable suspension. The inner hydrophobic PLGA layer prevents the PSiNPs from the dissolution in water, while the outer PVA layer makes the PSiNPs hydrophilic. The PL quantum yield of PLGA/PVA-coated PSiNPs was found to increase by three times for 2 weeks of the storage in water. The observed effect is explained by taking into account both suppression of the dissolution of PSiNPs in water and a process of the passivation of nonradiative defects in PSiNPs. The obtained results are interesting in view of the potential applications of PSiNPs in bioimaging.

Highlights

Optical techniques such as luminescent labeling are widely used in biomedicine today
Fluorescent indocyanine green and magnetic iron oxides embedded into polylactic-coglycolic acid (PLGA) nanoparticles were used for high resolution diagnostics of lymph nodes
Our results demonstrate that PLGA/ polyvinyl alcohol (PVA)-coated porous silicon nanoparticles (PSiNPs) possess the efficient PL for longtime storage in water

Summary

Introduction

Optical techniques such as luminescent labeling are widely used in biomedicine today. They are noninvasive and can be employed for in vitro and in vivo diagnostics. One example is in vitro tests on infectious diseases based on a photoluminescence (PL) response, e.g., Gram staining [1]. Another example is the optical coherent tomography, which is successfully employed to detect malignant tumors in vivo [2]. In this case the cost of a single analysis is several times lower than that of radiology treatment. The employed PLGA is a well-known biocompatible polymer for drug delivery applications [5]

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Results

Conclusion