About

Abby Whittington is an Associate Professor jointly appointed in the Department of Chemical Engineering and the Department of Materials Science and Engineering at Virginia Tech. She holds a Ph.D. from the University of Illinois at Urbana-Champaign, obtained in 2006, and a B.S. from Auburn University, earned in 2000. Her research interests include tissue engineering, biopolymers, controlled-release drug delivery, and cell-biomaterial interactions.

Research topics

• Biology
• Materials science
• Internal medicine
• Medicine
• Biomedical engineering
• Food science
• Surgery
• Nuclear chemistry
• Polymer chemistry
• Organic chemistry
• Composite material
• Chemistry
• Chemical engineering
• Radiology

Selected publications

• Dynamic Micromechanical Characterization of 3D Printed Bone In Vitro Models Manufactured via Vat Photopolymerization

  Advanced Functional Materials · 2025-03-06 · 5 citations

  articleOpen accessSenior authorCorresponding

  Abstract 3D in vitro organotypic bone models enable the study of human cells in an environment that mimics in vivo physiology and mechanobiology. However, creating large bone tissue scaffolds (≈1 cm 3 ) with fine feature sizes (≈200–400 µm) and interconnected porosity is not feasible at scale using traditional stochastic techniques. Thus, this study aimed to manufacture porous 3D scaffold geometries using a novel, osteoconductive resin via vat photopolymerization and analyze their ability to mimic the in vivo bone micromechanical environment. Scaffolds (n = 85) are printed with 80% porosity using an ESOA‐PEDGA. Resin After static culture with murine NIH 3T3 fibroblasts, the scaffolds are assessed to characterize print fidelity, proliferation behavior, and mechanical properties. After printing, each scaffold type closely resembled its targeted geometry. Uniform cell distribution is observed in all geometries during initial seeding, with significantly more cells throughout each scaffold after 7 days. Mechanical testing revealed the presence of cells, not just media, has a significant impact on stiffness for all geometries. Only Voronoi geometries have a significant increase in storage moduli during culture. These results confirm scaffold geometry is a critical factor affecting cell distribution, proliferation, and scaffold stiffness, which has significant implications for bone tissue‐engineered scaffolds.

  PublisherOA PDFDOI

• Reduced Sliding Friction of Lubricant-Impregnated Catheters

  ACS Omega · 2024-01-10 · 2 citations

  articleOpen access

  During urethral catheterization, sliding friction can cause discomfort and even hemorrhaging. In this report, we use a lubricant-impregnated polydimethylsiloxane coating to reduce the sliding friction of a catheter. Using a pig urethra attached to a microforce testing system, we found that a lubricant-impregnated catheter reduces the sliding friction during insertion by more than a factor of two. This suggests that slippery, lubricant-impregnated surfaces have the potential to enhance patient comfort and safety during catheterization.

  PublisherOA PDFDOI

• Embedding of Liquids into Water-Soluble Materials via Additive Manufacturing for Timed Release

  3D Printing and Additive Manufacturing · 2024-09-13

  article

  The ability to customize products with additive manufacturing allows manufacturers to meet the unique requirements and functionality for individual applications. By printing dissolvable materials as a matrix material, the release of active agents over time can be tailored on a per part basis by varying both geometry and printed material properties. Direct printing of actives via filament material extrusion is challenging because many active agents become inactive at the elevated temperatures found in the melt-based process. This limitation is circumvented by in situ embedding the active agents into a priori designed voids of a printed water-soluble capsule. In this work, this process is demonstrated by the in situ deposition of liquids and powders into thin-walled, water-soluble, printed structures. The authors demonstrate the ability to tune dissolution time by varying the thickness of a printed part’s walls in order to create a delay in release and by creating parts with multiple chambers to initiate a multistaged release. This ability provides opportunities for creating customized containers for the prescribed release of liquid and powdered active agents.

  PublisherDOI

• Clearance of Biodegradable Polymer and Polyethylene Films from the Rumens of Holstein Bull Calves

  Animals · 2023-03-03 · 6 citations

  articleOpen access

  Due to the occurrence of plastic impaction in ruminants and its deleterious effects on health and production, it is necessary to determine the suitability of biodegradable polymers to replace polyethylene-based agricultural plastics, such as hay netting. The objectives of this study were to evaluate the clearance of a polyhydroxyalkanoate (PHA) and poly(butylene succinate-co-adipate) (PBSA) melt-blend polymer from the rumen when fed to cattle and subsequent animal health. Twelve Holstein bull calves were dosed with an encapsulated 13.6 g of PBSA:PHA (Blend), 13.6 g of low-density polyethylene (LDPE), or four empty gelatin capsules (Control) for 30 d. The feed intake, body weight, and body temperature were evaluated, and hemograms were run on d 0 and d 30. On d 31, calves were euthanized to evaluate gross rumen measurements and pathology, papillae length, and polymer residues in rumen contents. No calves presented any signs related to plastic impaction. The feed intake; body weight; rectal temperature; hematological parameters; gross rumen measurements and pathology; and rumen pH and temperature were not affected by treatments. Calves dosed with LDPE had 27 g of undegraded polymer retained in the rumen while Blend calves had only 2 g of fragmented polymers that were 10% of their original size. Agricultural plastics developed from PBSA:PHA may be a suitable alternative to LDPE-based products in the case of animal ingestion and may reduce the incidence of plastic impaction.

  PublisherOA PDFDOI

• Stability of Aerosolized SARS-CoV-2 on Masks and Transfer to Skin

  Environmental Science & Technology · 2023-07-03 · 8 citations

  articleOpen access

  The potential for masks to act as fomites in the transmission of SARS-CoV-2 has been suggested but not demonstrated experimentally or observationally. In this study, we aerosolized a suspension of SARS-CoV-2 in saliva and used a vacuum pump to pull the aerosol through six different types of masks. After 1 h at 28 °C and 80% RH, SARS-CoV-2 infectivity was not detectable on an N95 and surgical mask, was reduced by 0.7 log10 on a nylon/spandex mask, and was unchanged on a polyester mask and two different cotton masks when recovered by elution in a buffer. SARS-CoV-2 RNA remained stable for 1 h on all masks. We pressed artificial skin against the contaminated masks and detected the transfer of viral RNA but no infectious virus to the skin. The potential for masks contaminated with SARS-CoV-2 in aerosols to act as fomites appears to be less than indicated by studies involving SARS-CoV-2 in very large droplets.

  PublisherOA PDFDOI

• PSXIII-B-2 Clearance of Poly(Butylene Succinate-co-Adipate):Polyhydroxyalkanoate and low-Density Polyethylene Films from the Rumens of Holstein Bull Calves

  Journal of Animal Science · 2022-09-21 · 1 citations

  articleOpen access

  Abstract Replacing undigestible, polyethylene-based agricultural plastics like net wrap with biodegradable alternatives polyhydroxyalkanoate (PHA) and poly(butylene succinate-co-adipate) (PBSA) may reduce the incidence of plastic impaction in ruminants. The objectives of this study were to evaluate the ruminal clearance of PBSA:PHA compared to low-density polyethylene (LDPE) and to evaluate animal health when these materials are fed. Twelve Holstein bull calves, blocked by age and weight, were randomly allocated to one of three daily bolus treatments for 30d: 13.6g of PBSA:PHA in 4 capsules (Blend), 13.6g of LDPE in 4 capsules (LDPE), or 4 empty capsules (Control). Hemograms were conducted on blood samples collected on d0 and d30. On d31, animals were sacrificed to evaluate gross rumen measurements, pathology, and papillae length, and to characterize polymer residues in rumen contents. Data were analyzed with PROC MIXED in SAS and least squared differences were adjusted by Tukey’s method. No animals presented any symptoms related to plastic impaction and animal health was not affected by treatment. Daily grain and hay intake, body weight, rectal temperature, hematological parameters, gross rumen measurements and pathology, and rumen pH and temperature were not affected by treatment. Methylene blue reduction time of Blend calves tended to be decreased by 30% compared to LDPE calves (P=0.06), and caudal ventral papillae length of Blend calves were 50% longer than those of Control animals (P< 0.01). Thus, PBSA:PHA may have beneficial impacts. Calves dosed with LDPE retained 27.42g of undegraded polymer in the rumen while 1.72g of fragmented polymers 10% of their original size were detected in Blend calves (P< 0.01). Our results indicate that if net wrap is developed from PBSA:PHA and incorporated into ruminant feed, aggregation of filamentous material will not occur in the rumen, and incidences of plastic impaction will be decreased compared to net wrap developed from LDPE.

  PublisherOA PDFDOI

• Developing Echogenic Materials as Catheters for Use with Ultrasound

  ACS Biomaterials Science & Engineering · 2022-02-16 · 1 citations

  articleSenior authorCorresponding

  Patients with peripherally inserted central catheters (PICCs) are routinely discharged with the catheters in place. These patients experience complications due to undetected thrombosis or accidental dislodgement, with tracking through limited X-ray imaging. Developing catheters with the capability to be tracked without the need for X-ray imaging would greatly benefit these patients by decreasing patient stress, reducing time to diagnosis, and increasing nursing home capabilities. This study reports on the incorporation of echogenic microspheres into catheters to produce bulk echogenic effects for developments in the field of real-time ultrasound tracking of polymeric medical devices. The impact on elastic modulus, ultrasound contrast, and cytocompatibility of the polymer was analyzed when incorporating up to 10 wt % glass microspheres. Up to this loading level, the elastic modulus was found to remain constant. However, at 10 wt %, extrusion defects due to agglomeration, air bubbles, and shearing were numerous and deemed detrimental to ultrasound imaging. Successful, defect-free samples were produced with 5 wt % microsphere loading and when embedded in a soft tissue phantom revealed a significant increase in the signal-to-noise ratio as compared to the polymer alone. Preliminary results have shown a successful increase in polymer's echogenic properties, without undermining its mechanical and cytocompatibility properties.

  PublisherDOI

• Digestibility Kinetics of Polyhydroxyalkanoate and Poly(butylene succinate-co-adipate) after In Vitro Fermentation in Rumen Fluid

  Polymers · 2022 · 7 citations

  • Materials science
  • Chemistry
  • Nuclear chemistry

  -adipate) (PBSA), PBSA:PHA melt blends, and forage controls were incubated in rumen fluid for up to 240 h. Mass loss was measured after each incubation time, and digestion kinetic parameters were estimated. Thermogravimetric, differential scanning calorimetry, and intrinsic viscosity analyses were conducted on incubated samples. Generally, across treatments, mass loss was significant by 96 h with a minimum increase of 0.25% compared to 0 h but did not change thereafter. Degradation kinetics demonstrated that polymer treatments were still in the exponential degradation phase at 240 h with a maximum disappearance rate of 0.0031 %/h. Melting temperature increased, onset thermal degradation temperature decreased, and intrinsic viscosity decreased with incubation time, indicating structural changes to the polymers. Based on these preliminary findings, the first stage of degradation occurs within 24 h and PHA degrades slowly. However, further ruminal degradation studies of biodegradable polymers are warranted to elucidate maximum degradation and its characteristics.

  PublisherOA PDFDOI

• Long-term in situ ruminal degradation of biodegradable polymers in Holstein dairy cattle

  JDS Communications · 2022-12-22 · 10 citations

  articleOpen access

  Using biodegradable materials such as polyhydroxyalkanoates (PHA) and poly(butylene succinate-co-adipate) (PBSA) to develop single-use agricultural plastics like bale netting may reduce the negative effects of plastic accumulation in the rumens of cattle. The objective of this research was to assess the long-term degradation of PHA, PBSA, and a PBSA:PHA blend (Blend) compared with a low-density polyethylene (LDPE) control. Polyhydroxyalkanoate, PBSA, Blend, and LDPE films were incubated in the rumens of 3 cannulated, nonlactating Holsteins for up to 150 d. In situ disappearance (ISD) and residue length were assessed after every incubation time. Data were analyzed with PROC MIXED in SAS and adjusted by Tukey's method to determine least squares differences between polymer treatments, incubation time, and their interaction. By 30 d, PHA achieved 100% degradation, with initiation occurring at 14 d indicated by ISD and a reduction in residue length. Poly(butylene succinate-co-adipate) and Blend did not achieve any significant ISD, but fragmentation of PBSA occurred at 60 d and fragmentation of Blend at just 1 d, likely due to abiotic hydrolysis. Low-density polyethylene achieved no ISD, and residue length did not change over incubation time. We propose that a PBSA:PHA blend is a valid alternative to polyethylene single-use agricultural plastic products based on its fragmentation within 1 d of incubation.

  PublisherOA PDFDOI

• Focused Ultrasound Biofilm Ablation: Investigation of Histotripsy for the Treatment of Catheter-Associated Urinary Tract Infections (CAUTIs)

  IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control · 2021 · 17 citations

  • Biomedical engineering
  • Medicine
  • Surgery

  reduction in CFU/mL after six histotripsy scans across the catheter mimics. Overall, the results of this study demonstrate the potential of histotripsy to provide a new modality for removing bacterial biofilms from catheter-based medical devices and suggest that additional work is warranted to investigate histotripsy for the treatment of CAUTIs and other biomaterial-associated infections.

  PublisherOA PDFDOI

Frequent coauthors

• Christopher B. Williams

  9 shared

• Timothy E. Long

  Arizona State University

  7 shared

• John H. Rossmeisl

  Virginia Tech

  7 shared

• Kristin M. Fischer

  Hampden–Sydney College

  6 shared

• André T. Stevenson

  6 shared

• Satyavrata Samavedi

  Indian Institute of Technology Hyderabad

  5 shared

• Shelley L. Cooke

  Virginia Tech

  5 shared

• Callie E. Zawaski

  Pennsylvania State University

  5 shared

Education

• PhD, Materials Science and Engineering

  University of Illinois at Urbana-Champaign

  2006

• BS, Summa cum Laude, Textile Chemistry

  Auburn University

  2000