DSPE-PEG-SH to DSPE-PEG-CONHNH2
DSPE-PEG-Amine to DSPE-PEG-SH
T1 - Analysis of functionalization of methoxy-PEG as maleimide-PEG
In addition to mechanical properties, presentation of immobilized biochemical signals on the ECM is also important in many biological applications. As has been shown in previous work, peptide ligands can be incorporated into PEGNB hydrogel networks via the sulfhydryl group of an exposed cysteine residue. We used the integrin binding peptide sequence CGGGRDGSP to test the efficiency with which small peptide ligands are incorporated into PEGNB hydrogels using thiol-ene chemistry. The amount of peptide incorporated into the hydrogel network was found to be proportional to the amount of peptide in the prepolymer solution, with higher incorporation efficiency at lower peptide concentrations (). Peptide incorporation into the hydrogel was not quantitative, likely due to factors such as mass transfer limitations and disulfide bond formation. Given that peptide incorporation is not quantitative, it is important to measure the peptide incorporated into the crosslinked hydrogel after crosslinking in order to report accurate ligand concentrations. The peptide ligand enabled NIH3T3 fibroblasts to attach to the surface of a hydrogel functionalized with the integrin binding peptide, and the gel had sufficient ligand density to allow the cells to spread on the surface of the gel ().
The mechanical properties of thiol-ene crosslinked PEG hydrogels can be formulated to achieve a wide range of compressive moduli. The stiffest hydrogels were formed using low-molecular-weight monomers in conjunction with a high degree of functionality and a high monomer loading in the prepolymer solution. Stiff hydrogels derivatized with an integrin binding peptide were able to allow cells to attach and spread on the surface. The peptide incorporated into the hydrogels was proportional to the concentration of the peptide in the prepolymer solution. The ability to bond individual hydrogel layers enables creation of microfluidic channels, and opens up the possibility of creating chemically and mechanically asymmetric cellular microenvironments.
4-Arm PEG-SH - Advanced BioChemicals
Li . designed folate receptor-targeted hollow gold nanospheres carrying siRNA recognizing NF-B, a transcription factor related to the expression of genes involved in tumor development [,]. In this case, the photothermal effects of gold nanospheres were utilized to regulate drug release and as a therapeutic tool. Core/shell-structured hollow gold nanospheres (HAuNS, 40 nm) were initially synthesized, consisting of a thin gold wall with a hollow interior, and the structures displayed strong surface plasmon resonance (SPR) tunability in the near-IR region [-]. Thiol-modified siRNA duplexes directed toward the NF-B p65 subunit were then introduced to the surface of HAuNS. Folates were coupled to the nanoparticles through a thioctic acid-terminated PEG linker to produce F-PEG-HAuNS-siRNA (Figure A and B). Irradiation with a pulsed near-IR laser (800 nm) altered the absorption spectra of the HAuNS-siRNA solutions significantly, indicating a loss in the structural integrity and triggering the dissociation of siRNA from HAuNS, when demonstrated by TEM and fluorescence microscopy images. This mode of action is termed 'photothermal transfection'. Intravenous injection of the nanospheres into HeLa xenografts resulted in the distinct downregulation of the NF-B p65 subunit only for the folate-conjugated nanosphere treatment combined with near-IR laser irradiation, suggesting that selective targeting and endolysosomal escape of the nanoparticles was activated by near-IR irradiation at the tumor site. tests, in which therapy was combined with administration of irinotecan, a chemotherapeutic agent that increases sensitivity to NF-B inhibition, yielded a substantially enhanced apoptotic response (Figure C). micro-positron emission tomography (PET))/computed tomography (CT) imaging also confirmed the folate-mediated tumor-targeted theranostic properties of the nanostructures (Figure D). Although significant uptake of the nanoparticles was observed in the liver, spleen, kidney, and lung, no significant downregulation of p65 in these organs was observed as a result of the tumor-selective near-IR irradiation.
(A) Schematic diagram showing bioconjugation of HAuNS-siRNA and photothermal-induced siRNA release. (B) Schematic diagram showing the synthesis of F-PEG-HAuNS-siRNA and the proposed intracellular events following near-IR irradiation. (C) Effect of p65 siRNA photothermal transfection combined with irinotecan delivered to nude mice bearing HeLa cancer xenografts. (D) Micro-PET/CT imaging of nude mice bearing HeLa cervical cancer xenografts in right rear leg 6 h after intravenous injection of F-PEG-HAuNS-siRNA(DOTA-64Cu) or PEG-HAuNS-siRNA(DOTA-64Cu). Arrowheads indicate the tumors. Reproduced with permission from ref. .
Miscellaneous Surface Reactive PEG Derivatives: Silane ..
Riboflavin is an essential vitamin for cellular metabolism, and the riboflavin carrier protein (RCP) is highly upregulated in metabolically active cells [,]. Thus, flavin mononucleotide (FMN), an endogenous RCP ligand, was used as a small molecule targeting ligand for metabolically active cancer or endothelial cells. Kiessling and co-workers synthesized FMN-coated ultrasmall superparamagnetic iron oxide nanoparticles (FLUSPIO) as MRI/optical dual probes for cancer detection . USPIO was coated with FMN through the phosphate groups of FMN, and guanosine monophosphate was added to stabilize the colloid. The hydrodynamic radius of FLUSPIO was 97 ± 3 nm, and an intense fluorescence emission band was observed at 530 nm due to FMN. cellular uptake of FLUSPIO was investigated by MRI (3T), TEM, and fluorescence microscopy of PC3 cells and HUVEC cells. Both PC3 cells and HUVEC cells showed a significantly higher R2 relaxation rate after 1 h incubation with FLUSPIO than with nontargeted USPIO. Such an uptake was considerably reduced by competitive blocking of RCP with free FMN. A strong green fluorescence in the cells was observed after FLUSPIO incubation. The perinuclear fluorescence signal suggested endosomal localization of the nanoparticles, consistent with TEM results, suggesting that FMN could serve as a versatile building block for generating tumor-targeted imaging and therapeutic modalities.
An example of a hydrothermal reaction is the synthesis of zinc oxide as proposed by Chen , using the reagents ZnCl2 and NaOH in a ratio of 1:2, in an aqueous environment. The process took place by way of reaction (5):
26/12/2017 · Synthesis of FITC-PEG 5000 ..
synthesis of maleimidophenyl-PEG ..
KW - Maleimidophenyl-PEG
Robust, Efficient, and Orthogonal Synthesis of …
We also achieved successful transdermal gelation via theNIR-assisted photothermal thiol-acryl reactions.
Amine synthesis by azide reduction - Organic chemistry
We also achievedsuccessful transdermal gelation via the NIR-assisted photothermalthiol-acryl reactions.
Categories: N-H Bond Formation > Reduction of azides
In summary, we report a simple method of synthesis of Pluronic micelle-encapsulated QDs as nanoprobes for cancer imaging. Our design was not only able to protect the QDs stable enough under physiological conditions but also can be conjugated with FA by the simple EDC chemistry conjugation technique, for targeted cancer imaging applications. The result of preliminary work with this nanoprobe appeared to be promising, which revealed the potential of this nanoprobe for application due to the negligible level of toxicity. We have confirmed the targeting of QD bioconjugates in a pancreatic tumor model using small animal imaging system.
MAL-dPEG®x-NHS ester Archives - Quanta BioDesign
Model thiol-maleimide conjugation between L-glutathione and maleimide 11a or PEG-MAL 11b (Mn = 5.0K), analogs of PCL-PEG-MAL copolymer, preceded well. Complete conversion of both glutathione and maleimide was obtained. Impingement mixing of PCL-PEG-MAL (8.6K-4.6K, 6.9K-4.6K or 4.6K-4.6K) and PCL-PEG (6.9K-4.6K) resulted in formation of maleimide surface-functionalized nanoparticles. The mass average sizes were ca. 20–40 nm. The amount of accessible maleimide functionality on the nanoparticle surfaces was estimated by Ellman analysis to be 51% and 67% conjugation for 8.6K-4.6K and 4.6K-4.6K PCL-PEG-MAL nanoparticles, respectively. We are pursuing this strategy as a means for conjugating other biologically relevant molecules (e.g., proteins, vaccines, or imaging agents) to these biocompatible particles.
MAL-dPEG®₂-NHS ester (#10266) Greg T
Li  proposed a method of preparing nanometric zinc oxide using a microemulsion which is formed when alcohol is added to an emulsion system consisting of water, oil and emulsifier, until a transparent mixture is obtained. In this case the microemulsion consists of a solution of heptane and hexanol together with a non-ionic surfactant (such as Triton X-100). The growth of nanoparticles involves the exchange of the substrates Zn(NO3)2 and NaOH between the microemulsion drops and the medium (poly(ethylene glycol)—PEG 400), and aggregation of the formed nuclei. Drops of microemulsion act as a microreactor in which the desired reaction takes place. In the synthesis of ZnO, different concentrations of PEG 400 were used (0%–50%). illustrates the process of synthesis in microemulsion and the shape of ZnO nanoparticles as proposed by the aforementioned authors.
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