文獻(xiàn)：MICRORHEOLOGICAL QUANTIFICATION OF CELL-MEDIATED REMODELING OF POLYMER-PEPTIDE HYDROGELS IN RESPONSE TO CHEMICAL CUES
摘要：
The next chapter describes the development of a new technique to create hydrogels with tethered concentration gradients of polymers or proteins. This technique also enables us to measure the diffusion coefficient of solutes in hydrogels. Hydrogels with tethered concentration gradients of cell signaling molecules can be used to direct cell migration from the scaffold to the wound after implantation. A rectangular prism is the basis of our microfluidic device. Before using the microfluidic device to create hydrogels with a tethered concentration gradient of TNF-α, we make concentration gradients with a model polymer, Fluorescein poly(ethylene glycol)-thiol (FITC-PEG-SH), to validate the technique. We first make a calibration curve by measuring hydrogels with known concentrations of FITC-PEG-SH and measure their arbitrary brightness using a laser scanner. This calibration curve relates brightness with tethered molecule concentration. We form hydrogels with tethered concentration gradients of FITC-PEG-SH by allowing the molecule to diffuse for 6, 24 and 48 hours. Hydrogels with tethered concentration gradients of FITC-PEG-SH are placed on the laser scanner and spatial brightness is measured. The calibration curve is then used to back-calculate local concentrations every 25 micrometers along the hydrogel. Next, we curve-fit a solution of Fick’s second law of diffusion to calculate the effective diffusion coefficient of FITC-PEG-SH. In the FITC-PEG-SH experiments, we hypothesize that steady state diffusion is reached when a gradient forms for 24 hours. We use the same method to make concentration gradients of thiolated and dyed TNF-α tethered into hydrogels.
該技術(shù)可以制造具有聚合物或蛋白質(zhì)束縛濃度梯度的水凝膠。該技術(shù)還使我們能夠測(cè)量水凝膠中溶質(zhì)的擴(kuò)散系數(shù)。具有細(xì)胞信號(hào)分子系留濃度梯度的水凝膠可用于在植入后引導(dǎo)細(xì)胞從支架遷移到傷口。矩形棱鏡是我們微流體裝置的基礎(chǔ)。在使用微流體裝置制造具有TNF-α束縛濃度梯度的水凝膠之前，我們用模型聚合物熒光素聚乙二醇硫醇（FITC-PEG-SH）制作濃度梯度，以驗(yàn)證該技術(shù)。
我們首先通過(guò)測(cè)量已知濃度的FITC-PEG-SH水凝膠來(lái)繪制校準(zhǔn)曲線，并使用激光掃描儀測(cè)量其任意亮度。該校準(zhǔn)曲線將亮度與系留分子濃度聯(lián)系起來(lái)。我們通過(guò)讓分子擴(kuò)散6、24和48小時(shí)，形成具有FITC-PEG-SH束縛濃度梯度的水凝膠。將具有FITC-PEG-SH束縛濃度梯度的水凝膠放置在激光掃描儀上，并測(cè)量空間亮度。然后使用校準(zhǔn)曲線沿水凝膠每25微米反向計(jì)算一次局部濃度。接下來(lái)，我們對(duì)菲克第二擴(kuò)散定律的解進(jìn)行曲線擬合，以計(jì)算FITC-PEG-SH的有效擴(kuò)散系數(shù)。在FITC-PEG-SS實(shí)驗(yàn)中，我們假設(shè)當(dāng)梯度形成24小時(shí)時(shí)達(dá)到穩(wěn)態(tài)擴(kuò)散。我們使用相同的方法使巰基化和染色的TNF-α的濃度梯度固定在水凝膠中。
測(cè)量比預(yù)測(cè)理論值快一個(gè)數(shù)量級(jí)的有效擴(kuò)散系數(shù)。在創(chuàng)建多個(gè)水凝膠復(fù)制品后，我們假設(shè)更快速的擴(kuò)散是由于TNF-α和水凝膠交聯(lián)劑之間的靜電吸引。這種方法可以放大或縮小，以制備具有系留濃度梯度的水凝膠，用于細(xì)胞遞送，或測(cè)量水凝膠中聚合物或蛋白質(zhì)的擴(kuò)散系數(shù)。
相關(guān)推薦：
AA-PEG-AA
Alkyne-PEG-SVA
PLGA(2K)-PEG-SC
DBCO-PEG-SVA
Gala-PEG-SCM
Gluc-PEG-SCM
SCM-S-PEG-S-SCM
SVA-PEG-SVA
SPA-PEG-SPA
SAS-PEG-SAS
GAS-PEG-GAS
SG-PEG-SG
以上文章內(nèi)容來(lái)源各類(lèi)期刊或文獻(xiàn)，如有侵權(quán)請(qǐng)聯(lián)系我們刪除！
齊岳微信公眾號(hào)
官方微信
庫(kù)存查詢(xún)