The aim of this work was to generate a tunable surface isoelectric point (sIEP), where the surface is modified with two molecules: a weak base (pyridine), carrying a pH dependent positive charge, and a derivative of a strong acid (sulfate), carrying a permanent negative charge in a physiologically relevant pH range. To this end, silicon surfaces were modified with 3-aminopropyltriethoxysilane. These amine-modified surfaces were subsequently derivatized into pyridine- or sulfate-modified surfaces. Then, the surface pKa of pyridine-modified surfaces was determined by a fluorescent nanoparticle adhesion assay (FNAA). Next, these values were used to calculate in which ratio the chemicals must be present in the reaction mixture to generate a mixed pyridine/sulfate-modified surface with a target sIEP. After preparing surfaces with a target sIEP, an FNAA with positively and negatively charged nanoparticles was used to verify the sIEP of the generated surfaces. The FNAA revealed that pyridine-modified surfaces had a pKa of 6.69 ± 0.18. When an sIEP was generated, negative nanoparticles bound to surfaces at pH values below the sIEP and positive nanoparticles bound at pH values above the sIEP. Furthermore, we found sIEP values of 5.97 ± 0.88 when we aimed for an sIEP of 6.2, and 7.12 ± 0.21 when we aimed for an sIEP of 7.1. Finally, the pH dependent binding and release of a negatively and positively charged (bio)polymer was investigated for a target sIEP of 7. A negatively charged polymer (poly(I:C)) was bound at a pH < sIEP and released at a pH > sIEP with a release efficiency of 85 ± 9% and a positively charged polymer (trimethyl chitosan) bound at a pH > sIEP and released at a pH < sIEP with a release efficiency of 72 ± 9%. In conclusion, we established a method for preparing modified silicon surfaces with a tunable sIEP, which can be used for pH-dependent binding and release of biomacromolecules.
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http://dx.doi.org/10.1021/la404654t | DOI Listing |
Bioelectrochemistry
November 2024
Life Science and Chemistry College, Hunan University of Technology, Zhuzhou 412007, China. Electronic address:
Early cancer diagnosis is paramount for enhancing treatment efficacy, extending patient survival, and improving the quality of life. We developed a highly sensitive electrochemical biosensor for the detection of target DNA (tDNA) associated with gastric cancer. This advancement integrates dual signal amplification strategies: bio-barcode amplification (BCA) and surface-initiated enzyme polymerization (SIEP), with copper nanoclusters (CuNCs) serving as signal labels.
View Article and Find Full Text PDFInt J Gynaecol Obstet
June 2024
Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Catholic University of Sacred Heart, Rome, Italy.
Objective: To evaluate whether acute histologic chorioamnionitis (HCA) diagnosed in the placenta may be associated with an increased occurrence of bronchopulmonary dysplasia (BPD) or death among extremely low gestational age neonates (ELGAN).
Methods: This Italian single-center case-control retrospective study involved ELGAN admitted to the neonatal intensive care unit between January 2019 and June 2022. Infants born from pregnant women with acute and severe HCA, identified as stage ≥2 and grade 2 HCA, (HCA-infants) were compared with infants of pregnant women without chorioamnionitis or with stage 1, grade 1 chorioamnionitis (no-HCA-infants).
Int J Gynaecol Obstet
October 2023
Society for the Investigation of Early Pregnancy (SIEP), New York, New York, USA.
The goal of induced or spontaneous labor is childbirth by vaginal delivery. Delivery after 37 weeks is desirable and associated with favorable maternal and newborn outcomes. Delivery facilities should have suitable staff and resources on site for antenatal services and delivery care.
View Article and Find Full Text PDFInt J Gynaecol Obstet
October 2023
Department of Biomedical Sciences, Humanitas University, Milan, Italy.
Cesarean delivery is an abdominal surgical procedure performed for child delivery when the vaginal route is not feasible or desired due to maternal/fetal indications. All childbirth facilities should be able to safely perform a cesarean, which is not the current reality. For planned cesarean delivery, the facility must be prepared for the patient.
View Article and Find Full Text PDFInt J Gynaecol Obstet
October 2023
The George Washington Milken Institute of Public Health, Washington, District of Columbia, USA.
Childbirth is an intense event in which decisions may need to be made in seconds to guarantee the health of both mother and newborn. Despite health systems and care approaches varying widely according to real-life scenarios, availability of facilities, beliefs, resources, staff, and geography, among others, optimal outcomes should be ensured worldwide. Triaging low-risk pregnancies from high-risk pregnancies is the first step to ensure proper allocation of resources.
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