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Beta and Alpha Particle Autoradiography
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Anders Örbom, Brian W. Miller, Tom Bäck
Use of the micropattern gas detector from AI4R has also seen an increase. For example, the group of Lumen and colleagues in 2019 who investigated the distribution of 111In-labelled dual-PEGylated thermally oxidized porous silicon nanoparticles in mice bearing breast cancer allografts [57]. They performed both ex vivo distribution studies and in vivo SPECT imaging but then used autoradiography to establish that the nanoparticle (due to its large size) did not penetrate very well into the tumours. Another study employing the AI4R BeaQuant system is from Bailly and colleagues in 2020, where authors investigated whether 64Cu or 89Zr-labeling was preferable for antibodies targeting CD138 in a syngeneic mouse model of multiple myeloma [58]. Both biodistribution and PET-imaging were employed and autoradiography used for studying the uptake of 89Zr in bone, as can be seen in Figure 30.7.
Engineered Nanoparticles for Drug Delivery in Cancer Therapy *
Published in Valerio Voliani, Nanomaterials and Neoplasms, 2021
Tianmeng Sun, Yu Shrike Zhang, Pang Bo, Dong Choon Hyun, Miaoxin Yang, Younan Xia
In many cases, nanoparticles in the endolysosomes or the cytoplasm must be destructed to a certain extent to allow for proper release of the payloads. For polymer nanoparticles, several strategies can be utilized to improve the efficiency of disassembly, including the use of enzyme-active linkers, acid-labile cross-linkers, pH-sensitive detergent, thermal-sensitive liposomes, and disulfide cross-linkers that are sensitive to a reducing environment [151]. In one example, Ithakissios and coworkers studied the use of nanoparticles based on PLGA-PEG copolymers for the delivery of cisplatin [152]. They found that the intracellular degradation of PLGA-PEG nanoparticles was dependent on their composition. With higher PEG content, the degradation rate of nanoparticles increased, resulting in a faster release of the encapsulated cisplatin. In another example, Tasciotti and coworkers reported a drug delivery system based on porous silicon nanoparticles, the so-called multistage nanovectors (MSVs) [153]. According to their results, the decomposition of MSVs was largely determined by the pore size, and MSVs with larger pore sizes were degraded more rapidly. Along with the tunable drug-loading capacity of MSVs, the controlled release of a drug could be realized through engineering of the pore size of MSVs.
Immunology
Published in Paul Pumpens, Single-Stranded RNA Phages, 2020
Next, a new method, using thin films of nanoporous silicon, was suggested for improving the sensitivity of the phage MS2 detection (Rossi et al. 2007). Such porous silicon surface−based biosensor allowed the detection limit of 2 × 107 pfu/mL. Therefore, the system exhibited sensitivity and dynamic range similar to the Luminex liquid array−based assay, while it outperformed the micro-array methods. Again, the polyclonal rabbit anti-MS2 antibodies were used by this approach.
Porous silicon based intravitreal platform for dual-drug loading and controlled release towards synergistic therapy
Published in Drug Delivery, 2018
David Warther, Ying Xiao, Fangting Li, Yuqin Wang, Kristyn Huffman, William R. Freeman, Michael Sailor, Lingyun Cheng
In recent years, porous silicon (pSi) has been investigated as a drug delivery platform (Anglin et al., 2008; Kumeria et al., 2017) and for the sensing of drug release (Xu et al., 2017a) due to its tunable pores for various sized payloads and its photonic properties in different biological conditions. We have demonstrated that hydrosylilated or oxidized pSi is well tolerated after intravitreal injection and can provide sustained delivery of either DNR or DEX (Cheng et al., 2008; Chhablani et al., 2013; Hartmann et al., 2013; Hou et al., 2016). The pSi particles in the vitreous degrade into silicic acid that is cleared from the eye along with the ocular fluid turnover (Nieto et al., 2013). We hypothesized that properly functionalized pSi could be dually loaded with the model drugs, DNR and DEX, to create a platform to simultaneously deliver two drugs in a controlled release manner for synergistic effect.
Recent trends and perspectives in enzyme based biosensor development for the screening of triglycerides: a comprehensive review
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Vinita Hooda, Anjum Gahlaut, Ashish Gothwal, Vikas Hooda
The advantage of easy fabrication, greater adsorption property and controllable pore size makes porous silicon a leading candidate for various applications. In addition, it is attuned with standard silicon processing technology. Porous silicon (PSi) is prepared from the p-type crystalline silicon, which was oxidized thermally. It is utilized to immobilize lipase enzyme, which hydrolyses triglycerides to fatty acids. In 2003, Reddy et al. fabricated a potentiometric biosensor based on porous silicon for the quantitative estimation of triglycerides. The schematic representation of the biosensor has been shown in Figure 4. PSi was employed as an enzyme reactor. The enzyme was immobilized via physical adsorption on to the oxidized porous silicon, which was made-up from silicon. The employment of enzyme solution- oxidized porous silicon-crystalline silicon structure was done to sense the changes in pH of the solution during the hydrolysis of tributyrin as a result of shift in the capacitance-voltage (C-V) characteristics. The change in pH was proportional to the concentration of triglycerides present in the solution. The sensitivity of the sensor was high along with good reproducibility and reversibility. The LOD of the proposed biosensor for triglyceride was 1 µM [38]. In 2016, Al-Hardan et al. developed a highly sensitive pH sensor, which utilized porous silicon (PSi) as an extended gate field-effect transistor (EGFET). They prepared PSi with pore sizes in the range of 500 to 750 nm and a depth of approximately 42 µm. Further when PSi was tested for sensing of hydrogen ion in different pH buffer solutions, it was revealed that the PSi had a sensitivity value of 66 mV/pH (a super Nernstian value). The sensor considers stability to be in the pH range of 2-12 was considered highly stable for the sensors based on PSi. The hysteresis values of the proposed PSi sensor were approximately 10.5 and 8.2 mV in the high and low pH loop, respectively [47]. Some of the drawbacks of these PSi based sensors include less specificity, high cost and complicated operation.
Intravitreal safety profiles of sol-gel mesoporous silica microparticles and the degradation product (Si(OH)4)
Published in Drug Delivery, 2020
Yaoyao Sun, Kristyn Huffman, William R. Freeman, Michael J. Sailor, Lingyun Cheng
In recent years, various forms of porous silicon (pSi) have been used as vehicles for drug delivery (Anglin et al., 2008; Salonen et al., 2008). For example, mesoporous silica nanoparticles have been extensively explored for drug delivery in general (Siafaka et al., 2016, 2019). Compared with traditional drug delivery vehicles, such as liposomes or polymer particulates, pSi offers tunable nano-scaled pores for variously-sized payloads and adjustable drug release rates (Hou et al., 2014). In addition, pSi can be modified using various surface chemistries to alter its degradation half-life (Cheng et al., 2008) and its degradation products are water-miscible for clean elimination (Nieto et al., 2013). These properties make pSi very attractive for intravitreal drug delivery (Nan et al., 2014). Generally, functionalized pSi has demonstrated good biocompatibility both in vitro (Alvarez et al., 2009) and in vivo (Bimbo et al., 2010). However, the eye is a special organ that demands clear media for clear vision and the sensory retina is completely exposed to pSi particles after intravitreal injection. Differing from other organs, the eye is minimally tolerable to adverse reactions or inflammation associated with the injection of foreign material into the vitreous. Some studies have reported concentration-dependent pSi cytotoxicity on retinal pigment epithelium cells in vitro (Korhonen et al., 2016). It is known that porous silicon is biodegradable into silicic acid (Si[OH4]), a material that is also naturally present in human tissues (Reffitt et al., 1999). Even so, the safety profile of silicic acid on ocular cells is scarce in the literature. Porous silicon is usually employed as a long-term drug delivery system, which means the retina and anterior segment will be constantly exposed to various concentrations of silicic acid because a large portion of the degradation product is eliminated through the anterior chamber of the eye globe (Nieto et al., 2013). In an in vivo study, inflammatory reactions were noted when a piece of pSi was implanted under the conjunctiva (Low et al., 2009). From our experience, we have also occasionally noted variable vitreous reactions following the intravitreal injection of empty pSiO2 particles prepared from electrochemical etching in the lab (Nieto et al., 2013). Interestingly, these occasional mild reactions do not occur with drug-loaded particles (Chhablani et al., 2013; Hartmann et al., 2013; Nan et al., 2014). It is possible that the loaded drug suppresses the reaction or that the drug loading process changes the surface properties of the pSiO2. The pSi particles reported in literature are fabricated from electrochemical etching using hydrofluoric acid in academic labs. Impurities may have been introduced during the etching, particle production, or surface functionalization, which may be responsible for the variable reactions observed.