Page 83 - IJB-9-3

International Journal of Bioprinting 3DP hydrogels to combat antibiotic-resistant bacteria

Table 3. Results of Rif MIC and rpoB genotyping
Strain Rif MIC (μg/mL) Amino acid position Nucleotide substitution Amino acid substitution
S. aureus RN4220 0.0019 No change No change No change
S. aureus Rif R ≥ 128 463 AGC→AGA S463R
471 GAC→GGC D471G
484 CGT→CAT R484H
S. aureus RN4220 after contact with GelMA- 0.0019 No change No change No change
C-NPs
S. aureus RN4220 after contact with GelMA- ≥ 128 463 AGC→AGA S463R
Rif-NPs 471 GAC→GGC D471G
484 CGT→CAT R484H
S. aureus AMC 201 8 No change No change No change
S. aureus AMC 201 after contact with ≥ 128 No change No change No change
GelMA-Rif-NPs
S. aureus AMC 201 after contact with 8 No change No change No change
GelMA-C-NPs
Changes compared to rpoB sequence of the NCBI Reference Sequence of S. aureus RN4220 (NZ_CP076105.1) are indicated.
hyaluronic acid hydrogel that prevented infection in a 3D-printed antibiotic-loaded hydrogels can be
bone fracture-related infection rabbit model , or the designed and applied for tissue engineering applications
[45]
coating of a prosthesis with tobramycin- and Van-loaded or coatings of medical implants for the prevention or
HA-PLA-PEG hydrogels . In view of the fast diffusion of treatment of bacterial infections. Combining antibiotics
[46]
compounds from hydrogels, providing a sustained release for prevention or treatment of antimicrobial infections
of antibiotics from hydrogels could be challenging. may be chosen for incorporation into the hydrogels to be
Therefore, in this work, we incorporated Rif-NPs and printed before implantation. In this study, we designed
Van-NPs within a hydrogel to obtain a sustained drug and developed 3D-printed gelatin-methacrylate (GelMA)
release. hydrogels carrying PLGA NPs loaded with Van, Rif, or a
Moreover, some antibiotics are not soluble in water, combination of both. This technology enables the design
so new approaches are needed to incorporate such and manufacturing of a personalized antimicrobial
hydrophobic drugs in the hydrogels. In this work, we application with a gradual and controlled antibiotic
included Van (hydrophilic) and Rif (hydrophobic) release system to prevent or treat bacterial infections.
in PLGA NPs using two different techniques: (i) the The antimicrobial activity was evaluated in vitro against
single (for hydrophobic drugs) and (ii) the double (for S. aureus strain RN4220 and RN4220 Rif- and RN4220
hydrophilic drugs) emulsion and evaporation process. The Van-resistant isolates of this strain and against the clinical
drug release from PLGA NPs using different molecular S. aureus strain AMC 201. The results showed the complete
weights was studied. A correlation between the molecular eradication of bacteria by the 3D-printed hydrogel with
weight and the release rate was observed for Rif-NPs and the dual antibiotic-release NPs. The combination of two
Van-NPs, showing that the low molecular weight had the antibiotics, such as Rif and Van, in PLGA NPs loaded in
highest release rate after 7 days. These results are aligned the GelMA hydrogel provided sufficient protection against
with previous studies. Makino et al. showed that the release different S. aureus strains, including the single antibiotic-
rate of Rif from PLGA microparticles was highly correlated resistant S. aureus strains. Importantly, contact of S. aureus
to the molecular weight . Ozalp et al. obtained similar RN4220 with the GelMA-Rif-NPs alone induced the
[47]
results in their study, where they analyzed the release of development of resistance against Rif, showing the danger
[48]
Van from PLGA NPs using different molecular weights . of using Rif alone. Interestingly, although Rif resistance was
They observed that the lowest molecular weight PLGA easily selected if the non-resistant S. aureus RN4220 were
showed the highest release rate of Van. Regarding the incubated with hydrogels releasing only Rif, the selection
endcap group of PLGA, an acid endcap was reported to of Rif resistance did not easily occur when S. aureus
show a significant faster release than an ester endcap, as the RN4220 resistant to Van were used. The resistance to Van
acid endcap group promotes the autocatalytic hydrolysis of prevented S. aureus to easily develop resistance to Rif. This
the polymer, and hence, a faster degradation and release of is an important notion since it means that the combination
the drug. All the PLGA polymers studied in this work were with Van enables Rif to kill S. aureus even when these have
acid endcap . developed resistance to Van.
[49]

Volume 9 Issue 3 (2023) 75 https://doi.org/10.18063/ijb.683