Silicon nanoparticles as contrast agents in the methods of optical biomedical diagnostics

Nanoparticles Produced via Laser Ablation of Porous Silicon and Silicon Nanowires for Optical Bioimaging

“…All SiNPs have the mean size smaller than 70 nm with polydisperse distributions which are characterized by standard deviation values in the range of 9–24 nm. Consequently, the obtained SiNPs are noticeably smaller than those fabricated by mechanical milling or ultrasonic grinding of PSi and SiNW matrices [ 11 , 13 , 17 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ].…”

“…All SiNPs have the mean size smaller than 70 nm with polydisperse distributions which are characterized by standard deviation values in the range of 9-24 nm. Consequently, the obtained SiNPs are noticeably smaller than those fabricated by mechanical milling or ultrasonic grinding of PSi and SiNW matrices [11,13,17,[23][24][25][26][27][28][29]. The SiNPs produced by PLAL of microporous silicon (Figure 4a,b) demonstrate larger mean sizes in comparison to the case of ablation of mesoporous silicon (Figure 4c,d and Table 1).…”

“…SiNPs are widely employed in fluorescence imaging either as contrasting agents [10,13,14] or sensors for quantitative measurements [15,16]. SiNPs-based contrast enhancement was demonstrated also in optical coherence tomography (OCT) [17,18] and magnetic resonance imaging [19]. Other SiNPs applications include tissue engineering [20], nonlinear-optical diagnostics [21], photo- [22] and ultrasound [23] hyperthermia.…”

“…Traditionally, porous silicon (PSi) structures are used in biophotonics applications [5,6]. A serious limitation for further advances in biomedicine is relatively large sizes of SiNPs provided by traditional fabrication techniques, such as mechanical milling [13,17,23,24] or ultrasonic grinding [11,[25][26][27] of PSi matrices. Usually, the mean size of mechanically crushed powder particles of PSi exceeds 100 nm (although the nanocrystals themselves, which form these particles, may be smaller).…”

“…Pulsed laser ablation in liquids (PLAL) technique allows to overcome this limitation and provides small mean sizes (5-100 nm) and chemical purity for biomedical applications of SiNPs simultaneously [14,17,18,[20][21][22]30]. However, to produce SiNPs with high concentration, this method requires either lasers with high pulse repetition rate and energy, or significant increase in exposure time.…”