About

Enrique Barrera is a Professor of Materials Science and NanoEngineering at Rice University. His research focuses on interface studies and processing of composites, coatings, and thin films, as well as the development of new materials systems that leverage the unique properties of fullerenes and nanotubes. He is actively involved in research on nanotechnology, including the formation of hybrid nanotube materials and the development of fully integrated nanotube composites. Dr. Barrera has been recognized for his achievements in research and education, as well as his efforts in minority mentoring and recruitment to engineering. His awards include the NASA Group Achievement Award, the NASA National Research Council Senior Fellow at the Johnson Space Center, the National Science Foundation Young Investigator Award, the Presidential Award for Excellence in Science, Mathematics and Engineering Mentoring, and the Hispanic Engineering National Achievement Award Conference Award. He is also the chief technical officer of NanoRidge Materials, Inc., which specializes in advanced nanomaterials manufacturing. He holds a Ph.D., M.S., and B.S. from the University of Texas. His teaching areas include materials science, mechanical properties, analytical spectroscopies, composite materials, and nanocomposites. Dr. Barrera is a member of several professional organizations, including the American Society of Materials (ASM) and The Materials Society (TMS). He has contributed to education through his recognized K-12 program, the Materials Magic Show, which he and his students present to local schools.

Research topics

• Nanotechnology
• Materials science
• Chemistry
• Composite material
• Polymer chemistry
• Organic chemistry
• Chemical engineering
• Engineering
• Biomedical engineering

Selected publications

• Carbonaceous nanomaterials incorporated biomaterials: The present and future of the flourishing field

  Composites Part B Engineering · 2022 · 127 citations

  • Nanotechnology
  • Materials science
  • Engineering
  PublisherDOI

• Aspects of Coatings on Buckypaper as a Study into the Expected Effects of Coatings on Carbon Nanotube Wires

  Coatings · 2021-06-22

  articleOpen access

  Buckypaper (BP) was used as an accumulation of nanotubes to simulate as carbon nanotube (CNT) wires to study the interaction between four different insulating coating materials and CNTs. The wettability and electrical conductivity performance of each CNT/coating pair was assessed. The BP was prepared by filtering a sonicated solution of single-walled carbon nanotubes and N,N-Dimethylformamide, through a polytetrafluoroethylene (PTFE) membrane of 0.45 µm pore size. It was observed with Scanning Electron Microscopy, its chemical composition determined by X-ray Photoelectron Spectroscopy, its imperfections and purity measured by Raman Spectroscopy and the porosity (%) and pore distribution obtained by Nitrogen Physisorption. The results showed similar porosity and surface structure to that of reported CNT wires. The surface free energy of the BP was obtained through the Owens-Wendt method, and surface tension of the coatings was calculated with pendant drop measurements to find the adhesion and wettability parameters. Epoxy resin showed the highest wettability and adhesion, which resulted in infiltration into the BP that decreased electrical conductivity by 65%. In contrast, the insulating varnish showed much lower level of wettability and adhesion which resulted in the lowest decrease in conductivity (9.3%).

  PublisherOA PDFDOI

• Covalently Functionalized Carbon Nano-Onions Integrated Gelatin Methacryloyl Nanocomposite Hydrogel Containing γ-Cyclodextrin as Drug Carrier for High-Performance pH-Triggered Drug Release

  Pharmaceuticals · 2021 · 95 citations

  Senior authorCorresponding
  • Polymer chemistry
  • Chemical engineering
  • Chemistry

  ), and Young's modulus (E = 41.8 ± 1.4 GPa). The strengthening of GelMA/f-CNOs/CD hydrogel systems indicates its good dispersion and the degree of polymer enveloping of f-CNOs within GelMA matrixes. Furthermore, the obtained hydrogels showed improved cell viability with human fibroblast cells. Nevertheless, the primed supramolecular hydrogels would pave the way for the controlled delivery systems for future drug delivery.

  PublisherOA PDFDOI

• Carbon Nano-Onions Reinforced Multilayered Thin Film System for Stimuli-Responsive Drug Release

  Pharmaceutics · 2020 · 53 citations

  Senior authorCorresponding
  • Materials science
  • Chemical engineering
  • Composite material

  of toughness (K). Quantitative scrutiny revealed that the well-ordered aligned nanofibers provide critical interphase, and this could be responsible for augmented tensile properties. Nonetheless, a pH-responsive and mechanically robust biocompatible thin-film system may show potential applications in the biomedical field.

  PublisherOA PDFDOI

• 029 Biomechanical Effects of Rear Tip Extenders on Inflatable Penile Implants: A Cadaveric Study

  The Journal of Sexual Medicine · 2019-03-29 · 2 citations

  article

  It is speculated by many penile prosthesis implanters that rear tip extenders (RTEs) negatively affect axial loading so they should be avoided if possible but many implanters use RTE to assist with exit tubing angle thus justify their presence. However, the biomechanical effects of RTEs in the body have not been reported. In this study, two groups of Coloplast Titan inflatable penile implant (IPP) IPP-RTE pairs of total length of 20 and 24cm, respectively with lengths of RTEs ranging from 0, 2 and 4cm have been investigated to provide experimental evidence. 3 cadavers were obtained. Penile stretch length, corporal length, and pendulous shaft dimensions were obtained. Artificial erections and cavernosograms were performed on the 3 cadavers and one was excluded for Peyronie’s disease. The IPPs were surgically placed into two fresh cadavers via a penoscrotal technique by a high volume surgeon. The implants were confirmed to be placed correctly using fluoroscopy. The IPPs were assessed by column compression and cantilever deflection. A biomechanical evaluation of the properties of each IPP-RTE pairs inside the fibroelastic tunica albuginea was based on industry standard methods for assessment at 1034mmHg (20psi) fill pressure. X-ray images were obtained before and after kink formation.

  PublisherDOI

• Development of Functionalized Carbon Nano-Onions Reinforced Zein Protein Hydrogel Interfaces for Controlled Drug Release

  Pharmaceutics · 2019-11-20 · 82 citations

  articleOpen accessSenior author

  In the current study, poly 4-mercaptophenyl methacrylate-carbon nano-onions (PMPMA-CNOs = f-CNOs) reinforced natural protein (zein) composites (zein/f-CNOs) are fabricated using the acoustic cavitation technique. The influence of f-CNOs inclusion on the microstructural properties, morphology, mechanical, cytocompatibility, in-vitro degradation, and swelling behavior of the hydrogels are studied. The tensile results showed that zein/f-CNOs hydrogels fabricated by the acoustic cavitation system exhibited good tensile strength (90.18 MPa), compared with the hydrogels fabricated by the traditional method and only microwave radiation method. It reveals the magnitude of physisorption and degree of colloidal stability of f-CNOs within the zein matrix under acoustic cavitation conditions. The swelling behaviors of hydrogels were also tested and improved results were noticed. The cytotoxicity of hydrogels was tested with osteoblast cells. The results showed good cell viability and cell growth. To explore the efficacy of hydrogels as drug transporters, 5-fluorouracil (5-FU) release was measured under gastric and intestinal pH environment. The results showed pH-responsive sustained drug release over 15 days of study, and pH 7.4 showed a more rapid drug release than pH 2.0 and 4.5. Nonetheless, all the results suggest that zein/f-CNOs hydrogel could be a potential pH-responsive drug transporter for a colon-selective delivery system.

  PublisherOA PDFDOI

• MRS Communications Abstracts

  MRS Bulletin · 2019-01-01

  articleOpen accessSenior author
  PublisherOA PDFDOI

• 122 In-vivo Biomechanical Comparison of the Effects of Rear Tip Extenders on Penile Implants

  The Journal of Sexual Medicine · 2018-02-01

  article

  A biomechanical study of the AMS CX, AMS LGX, and Coloplast Titan inflatable penile prosthesis (IPP) was conducted where the effect of rear tip extenders was compared in a three cadaver in vivo study. Certified and recognized surgeons inserted the IPPs and recognized scientists and engineers conducted biomechanical testing using approaches that were correlated to standard test methods. Longitudinal compression, modified cantilever deflection, and flexural 3-point bending were used to compare the three IPPs where each were surgically inserted with 1cm, 1.5cm, or 2cm rear tips in three cadavers and inflated to 10psi and 20psi conditions. Furthermore for a corporal length IPP of 20cm made by using an 18cm + 2cm rear tip, a 20cm IPP with no rear tip was tested for comparison. Compression, modified cantilever, and bend data were acquired for the in vivo IPPs. Analysis was assessed based on kink formation in compression, max loading in cantilever testing and 3-point bend testing. Rigidity was also used to assess rear tip effects. Testing order, sequence, and pressure level were other parameters for the assessment.

  PublisherDOI

• Biomechanical Comparison of Inflatable Penile Implants: A Cadaveric Pilot Study

  The Journal of Sexual Medicine · 2018-06-28 · 27 citations

  article

  BACKGROUND: Throughout the last decade there has been a growing interest in the biomechanical differences between inflatable penile prostheses (IPPs) and their significance with regard to the patient experience. AIM: To present our findings assessing the biomechanical properties of IPPs with and without rear tip extenders (RTEs). METHODS: This is a biomechanical study of the 3 most commonly used IPPs (AMS CX, AMS LGX, and Coloplast Titan) as assessed by column compression, modified cantilever deflection, and 3-point bending methods. The IPPs were surgically placed into 3 fresh cadavers via an infrapubic technique by a single large-volume implanter. A biomechanical evaluation of the properties of each IPP inside the fibroelastic tunica albuginea was assessed in blinded testing, and analyses were based on industry standard methods for assessment. OUTCOMES: Maximum axial load; kink formation; horizontal stiffness; and resistance to 3-point flexure testing were measured. RESULTS: At maximum inflation, all 3 implants had similar performance. Differences appear to be most affected by fill pressures. In fact, only the AMS LGX at less than maximum inflation (LTMI) was unable to consistently withstand the roughly 0.9 kg (2 lbs) of pressure for column load testing mimicking vaginal intromission. The Coloplast Titan showed slightly better rigidity than the AMS LGX and CX devices in horizontal load testing, and, with 3-point flexure testing, the CX showed the best rigidity in the shortest phallus (A). Overall, the Titan showed slightly better rigidity in the longest phallus (C) and the phallus with mild Peyronie's disease (B). CLINICAL TRANSLATIONS: Penile implants with circumferential expansion had higher rigidity on biomechanical testing and should be considered in a patient's decision during selection of a penile implant. STRENGTHS AND LIMITATIONS: Strengths include blinding of the biomechanical testing and analyses, surgical procedures performed by a highly experienced surgeon, and that this is the "closest to" in vivo evaluation (inside the tunica albuginea) of penile implant function and properties to date. Weaknesses are that this study was performed in cadavers and not in live patients. It also has a small sample size, including the use of only 3 cadavers, and there was no correlation of performance to patient satisfaction. CONCLUSION: The results of this study support the conclusion that all devices are capable of functionally restoring erectile capacity. However, we observed that, in general, the 2 circumferentially expanding penile prosthesis showed greater resistance in biomechanical testing when compared with longitudinal and circumferential expanding devices. This should be considered as a guide during device selection for a patient undergoing penile prosthesis. Wallen JJ, Barrera EV, Ge L, et al. Biomechanical Comparison of Inflatable Penile Implants: A Cadaveric Pilot Study. J Sex Med 2018;15:1034-1040.

  PublisherDOI

• Development of forcespun fiber-aligned scaffolds from gelatin-zein composites for potential use in tissue engineering and drug release

  MRS Communications · 2018-05-10 · 38 citations

  article
  PublisherDOI

Frequent coauthors

• Valéry N. Khabashesku

  Rice University

  27 shared

• Narsimha Mamidi

  University of Wisconsin–Madison

  25 shared

• Irasema Lopez Romo

  Rice University

  21 shared

• Stefaan Decoutere

  IMEC

  16 shared

• Borga

  Rice University

  16 shared

• Matteo Meneghini

  16 shared

• Ming Zhao

  Carnegie Mellon University

  16 shared

• E. Zanoni

  University of Padua

  16 shared

Awards & honors

• NASA Group Achievement Award (2001)
• NASA National Research Council Senior Fellow at the Johnson…
• National Science Foundation Young Investigator Award (1993)
• Presidential Award for Excellence in Science, Mathematics an…
• Hispanic Engineering National Achievement Award Conference A…